# can 6 phase VRM boards handle 3900X? would like feedback from people who tried it



## terroralpha (Jan 23, 2020)

hello,

i'm looking to build an ITX computer with a 3900X. i would like to use a B450/X470 board because they don't have any chipset fans. i have no use for PCI E 4 and don't need the extra heat and noise in this small case. however, i'm not sure if any of the existing B450/X470 boards can handle a 3900X going HAM while editing video or occasional gaming. 

it looks like the 4xx boards with the best VRM are the asus B450 and MSI B450. both have 6 phase, 60A/phase VRMs. i'm not sure how the math works here but i do know that the 3900X has a 150W hard power limit. if i understand it correctly, the VRMs will work at around 1.2V, multiplied by 60A and then by 6 (# of VRMs). so, 1.2V x60A x6 = 432W max power delivery? does that mean that the B450 board will be OK with it long term?

i don't plan on hardcore OCing, but i will probably flip on PBO.

any ideas? or better yet, is anyone running a 3900X on a 6 phase VRM board?


----------



## cucker tarlson (Jan 23, 2020)

good 6 phase ? of course.


----------



## robot zombie (Jan 23, 2020)

Yep! Running mine on a Strix x370-f with 6 60A IR power phases and it runs on point. Just enabled PBO and it ran right up to expected performance. Still has more to give. No signs of strain on the VRMs whatsoever.


----------



## cucker tarlson (Jan 23, 2020)

robot zombie said:


> Yep! Running mine on a Strix x370-f with 6 60A IR power phases and it runs on point. Just enabled PBO and it ran right up to expected performance. Still has more to give.


that is true 6 phase and quality components
i'm a little afraid the op is talkling about 3 phase with a doubler on some crappy isl

for reference





						AM4 Vcore VRM Ratings v1.4 (2019-11-07) - Google Drive
					






					docs.google.com


----------



## robot zombie (Jan 23, 2020)

cucker tarlson said:


> that is true 6 phase and quality components
> i'm a little afraid the op is talkling about 3 phase with a double on some crappy isl


Ooo yeah... that would be iffy.

EDIT: Removing bad info... I was remembering overclocking a different CPU, thinking my 3900x did over 200w when all I had to do was check my saved benches to see it was actually more like 125w.    I need to not post at work, I think...


----------



## Ozymandias (Jan 23, 2020)

AM4 Vcore VRM Ratings v1.4 (2019-11-07)
					

AM4 Vcore VRM Ratings v1.4  AM4 Vcore VRM Ratings v1.4 (2019-11-07)  By Cr1318 (Reddit) Cautilus#5912 (Discord)  (I don't accept random friend requests on Discord, but you can send me a question on there if you share a server with me, you can find me on the discord.gg/overclock server,  otherwise...




					docs.google.com
				




I'm running a 3900X on an X370.
Admittedly it's on an VI Extreme which handles it with ease.





						New AMD mid-year build
					

Build Log...  [UPDATE 26/07/19] This build is now complete. :cool:    The rest of the pretty pictures: https://www.guernsey-ci.com/public/ocuk/index.php?dir=New AMD Build  Purchased.   Fractal Design Arc Midi R2 ITX case (Picked up on clearance for next to nothing) Icy Dock ToughArmor MB607SP-B...




					forums.overclockers.co.uk
				




Also running a 3900 (non-x) on a X570 TUF.





						Shoe String Budget Build (Gaming Rig Upgrade)
					

[BUILD COMPLETE]     This build is to replace and upgrade my ageing i7 6700k mITX gaming rig I built in 2016.    So this build had under gone a few upgrades since the initial day one build in early 2020. But I think I'm finally at a point in mid 2021 where I can say that I'm happy where it is...




					forums.overclockers.co.uk
				




_[EDIT] Beaten to it._


----------



## tabascosauz (Jan 23, 2020)

The Strix and MSI ITX B450s are just fine. 6 true Vcore phases with 40A and 60A PowIR respectively, IR35201.

The 3900X isn't that much a monster on power draw when not forced to run on fixed frequencies. As with anything without an active VRM fan, ensure decent airflow. PBO doesn't increase wattage much. Too many other limits in place 

The Aorus ITX uses good components but the heatsink is subpar and it lacks on phases, making it a bit hot for >8 cores even with 50A PowIRs on IR35201 like the other two. The other ASRock B450 is utter trash.

These PowIRs are the top dogs of yesteryear. This X570 ITX generation is filled with brand spanking new IR TDAs and Vishay SPSes instead, but again, overkill on 3900X.


----------



## terroralpha (Jan 23, 2020)

cucker tarlson said:


> that is true 6 phase and quality components
> i'm a little afraid the op is talkling about 3 phase with a doubler on some crappy isl
> 
> for reference
> ...


i'm not. the two boards i mentioned are both true 6 phase VRM boards. those are the only two 4xx series boards i'm looking at. going to avoid asrock like the plague this time around due to their junk VRM.



tabascosauz said:


> The Strix and MSI ITX B450s are just fine. 6 true Vcore phases with 40A and 60A PowIR respectively, IR35201.



oh damn, good call. i thought all the phases on the asus were 60A, turns out it was only the SOC VRM that's 60A. looks like i'll be buying my first ever MSI board.


----------



## tabascosauz (Jan 23, 2020)

terroralpha said:


> oh damn, good call. i thought all the phases on the asus were 60A, turns out it was only the SOC VRM that's 60A. looks like i'll be buying my first ever MSI board.



I mean, I'm not sure you'll ever even get close to 40Ax6=240A of power draw on a PB 3900X...the new TDA21472 (70A) equipped X570 boards are beginning to approach "too-good" territory, where the hardware spends the vast majority of its time in a power band where the efficiency is actually undesirable on the new smart power stages. Remember that all of these PowIRs and SPSes are rated for *maximum* current, and that you'll have to get within throwing distance of that number to actually achieve peak efficiency. Too overkill / too little power draw and they're actually not very efficient.

Depends on what you're after, I guess. I'll never opt for for a board that places an NVMe M.2 on the back of the board (the MSI ITX). The Strix has got two 3.0 x4s, but the second shares bandwidth with the x16 slot. MSI also has a shittier wifi card (not hard to replace) than the Aorus and Strix, as well as shittier LAN (the other two have i211), but it's not a big deal for most people. The big selling point of the Strix and MSI are the extra two true phases, which really reduce the heat on the pitifully designed heatsinks that all 3 of them have.


----------



## JackCarver (Jan 23, 2020)

Get the MSI B450I Gaming with 60A power stages. The two Ryzen 3900X/3950X have 95A-140A current draw. 95A most of the time with spikes to 140A. If you do a little overclocking it will be higher. If you look at the efficiency graph of the IR 40A and the IR 60A power stages you see, that the efficiency of the 60A stages is better with 6 phases than the efficiency of the 40A stages:






With 100A current output every phase has to handle 17A, so you are still in a very good efficiency here. Power Loss and heat dissipation is here less than 2 Watts per stage.
With the 40A stages of the Asus Board it looks like:






So with 17A per stage efficiency is not as good as with 60A stages as you can see. Power Loss is here at 2 Watts per stage. So with overclocking the 60A stages will be way better here.

Edit:
If you choose another brand then no problem, but be sure to get 60A stages.


----------



## terroralpha (Jan 23, 2020)

@tabascosauz i was going to say that, according to my memory, the bigger power stages should be more efficient overall even at low power draw, and therefor output less heat in to the ITX chassis i'll be putting this in. @JackCarver posted the actual efficiency charts just above me. the difference is small, the 60A stages are about 2%-3% more efficient, but they have more headroom.

looks like a 3900X with PBO will have the 40A stages running at about 50% load, that will probably torpedo the life of the board. 60A is probably the better choice here.

i'll probably be replacing the heatsink on whichever board i get with a proper one.


----------



## tabascosauz (Jan 23, 2020)

terroralpha said:


> @tabascosauz i was going to say that, according to my memory, the bigger power stages should be more efficient overall even at low power draw, and therefor output less heat in to the ITX chassis i'll be putting this in. @JackCarver posted the actual efficiency charts just above me. the difference is small, the 60A stages are about 2%-3% more efficient, but they have more headroom.
> 
> looks like a 3900X with PBO will have the 40A stages running at about 50% load, that will probably torpedo the life of the board. 60A is probably the better choice here.
> 
> i'll probably be replacing the heatsink on whichever board i get with a proper one.



You don't need to go those kinds of lengths; this isn't AM3+. Just get some air moving over the heatsink and you'll be plenty fine.

What case is this going into, and what is the 3900X cooled with? Anything larger and traditionally laid out like a QBX or H200i, just treat it as you would any other ATX build.


----------



## terroralpha (Jan 23, 2020)

tabascosauz said:


> You don't need to go those kinds of lengths; this isn't AM3+. Just get some air moving over the heatsink and you'll be plenty fine.
> 
> What case is this going into?



fully watercooled node 202. see attached picture. 

it's currently running an overclocked 8600k + RTX 2080 super.


----------



## JackCarver (Jan 23, 2020)

terroralpha said:


> @tabascosauz i was going to say that, according to my memory, the bigger power stages should be more efficient overall even at low power draw, and therefor output less heat in to the ITX chassis i'll be putting this in. @JackCarver posted the actual efficiency charts just above me. the difference is small, the 60A stages are about 2%-3% more efficient, but they have more headroom.
> 
> looks like a 3900X with PBO will have the 40A stages running at about 50% load, that will probably torpedo the life of the board. 60A is probably the better choice here.
> 
> i'll probably be replacing the heatsink on whichever board i get with a proper one.



With stock settings the 40Amps stages will be enough, but with oc and spikes to 200Amps for example every stage has to handle 33,33A. The 60A stages are still in the 90s here with about 18W heat dissipation. The 40A are at 86% with 36W heat dissipation. So a good heatsink is here definitely necessary.


----------



## tabascosauz (Jan 23, 2020)

terroralpha said:


> fully watercooled node 202. see attached picture.
> 
> it's currently running an overclocked 8600k + RTX 2080 super.



@terroralpha Is that a Z390 PG/ac? If you're not having any thermal problems overclocked on that toasty power delivery setup, you won't have any trouble here. It really isn't that beefy, save for the heatpipe which is of limited usefulness in that application. But short of some hard 9900K OC it's just fine with some airflow; same goes here for the 6-phase MSI. Even if you replace the Vcore heatsink with aftermarket copper ones a la AM3, if your case is airflow limited it won't do you a lot of good. A good ol' fan goes a long, long way.

@JackCarver Also, I'm not sure where this "200A spikes" number is coming from. Do you own a Zen 2 platform? Stock EDC (short-term) limit is 140A; PBO won't take his chip far past that, you have to run fixed freq for that. And like I've said a billion times, fixed freq is not the way to go.


----------



## terroralpha (Jan 23, 2020)

tabascosauz said:


> Is that a Z390 PG/ac? If you're not having any thermal problems overclocked on that toasty power delivery setup, you won't have any trouble here.


Yep, I had no problem with it. But that board has a beefy heatsink on the CPU VRM


----------



## lexluthermiester (Jan 23, 2020)

terroralpha said:


> hello,
> 
> i'm looking to build an ITX computer with a 3900X. i would like to use a B450/X470 board because they don't have any chipset fans. i have no use for PCI E 4 and don't need the extra heat and noise in this small case. however, i'm not sure if any of the existing B450/X470 boards can handle a 3900X going HAM while editing video or occasional gaming.
> 
> ...


Do you have a specific board in mind? If it is of sufficient quality, 6-phase power will do fine.


----------



## terroralpha (Jan 23, 2020)

lexluthermiester said:


> Do you have a specific board in mind? If it is of sufficient quality, 6-phase power will do fine.


yep, i mentioned both of them in the OP. asus B450 ITX and msi B450 ITX. will be going with the MSI


----------



## lexluthermiester (Jan 23, 2020)

terroralpha said:


> yep, i mentioned both of them in the OP. asus B450 ITX and msi B450 ITX. will be going with the MSI


You didn't mention board make or models, thus my comment. Not all B450 boards are made equal. I've seen budget models that have only 4-phase power to the CPU.


----------



## tabascosauz (Jan 23, 2020)

lexluthermiester said:


> You didn't mention board make or models, thus my comment. Not all B450 boards are made equal. I've seen budget models that have only 4-phase power to the CPU.



He said he wanted to build ITX. He said he was looking for B450. There are only 4 choices there, one of which is trash, one of which is unsuitable for >8 cores, and two that are actual contenders.

@terroralpha I hope you don't mind audio / have a better audio solution ready. MSI one is ALC887, a name I haven't seen in a long, long time.


----------



## terroralpha (Jan 23, 2020)

tabascosauz said:


> He said he wanted to build ITX. He said he was looking for B450. There are only 4 choices there, one of which is trash, one of which is unsuitable for >8 cores, and two that are actual contenders.
> 
> @terroralpha I hope you don't mind audio / have a better audio solution ready. MSI one is ALC887, a name I haven't seen in a long, long time.



Nope. Don’t care. I’m using a Bluetooth headset anyway. Even if there was no audio output at all i wouldn’t care. Thanks for the heads up though.


----------



## Durvelle27 (Jan 23, 2020)

3900X worked just fine on my B350 Board


----------



## lexluthermiester (Jan 23, 2020)

tabascosauz said:


> He said he wanted to build ITX. He said he was looking for B450. There are only 4 choices there, one of which is trash, one of which is unsuitable for >8 cores, and two that are actual contenders.


I found 6 that meet the requirements stated in the OP.








						ASRock B450M Steel Legend AM4 Micro ATX Motherboard - Newegg.com
					

Buy ASRock B450M Steel Legend AM4 AMD Promontory B450 SATA 6Gb/s Micro ATX AMD Motherboard with fast shipping and top-rated customer service. Once you know, you Newegg!




					www.newegg.com
				











						MSI Performance Gaming B450I Plus AC Mini ITX Motherboard - Newegg.com
					

Buy MSI PERFORMANCE GAMING B450I GAMING PLUS AC AM4 AMD B450 SATA 6Gb/s Mini ITX AMD Motherboard with fast shipping and top-rated customer service. Once you know, you Newegg!




					www.newegg.com
				











						ASUS ROG STRIX B450-I GAMING AM4 Mini ITX AMD Motherboard - Newegg.com
					

Buy ASUS ROG STRIX B450-I GAMING AM4 AMD B450 SATA 6Gb/s USB 3.1 HDMI Mini ITX AMD Motherboard with fast shipping and top-rated customer service. Once you know, you Newegg!




					www.newegg.com
				











						GIGABYTE B450 I AORUS PRO WIFI AM4 Mini ITX AMD Motherboard - Newegg.com
					

Buy GIGABYTE B450 I AORUS PRO WIFI AM4 AMD B450 SATA 6Gb/s USB 3.1 HDMI Mini ITX AMD Motherboard with fast shipping and top-rated customer service. Once you know, you Newegg!




					www.newegg.com
				











						ASUS ROG Strix X470-I Gaming AM4 Mini ITX AMD Motherboard - Newegg.com
					

Buy ASUS ROG Strix X470-I Gaming AM4 AMD X470 SATA 6Gb/s USB 3.1 HDMI Mini ITX AMD Motherboard with fast shipping and top-rated customer service. Once you know, you Newegg!




					www.newegg.com
				











						ASRock Fatal1ty X470 Gaming-ITX/ac AM4 Mini ITX AMD Motherboard - Newegg.com
					

Buy ASRock Fatal1ty X470 Gaming-ITX/ac AM4 AMD Ryzen 3000 Series CPU Ready Mini ITX AMD Motherboard with fast shipping and top-rated customer service. Once you know, you Newegg!




					www.newegg.com
				



Every one of these will work well for the OP's needs.


----------



## JackCarver (Jan 23, 2020)

VRM wise the MSI B450I Gaming is the best.


----------



## Zach_01 (Jan 23, 2020)

A 3900X will hit the 140A on heavy all core load. This is the first PBO limit the CPU finds, called EDC “Electrical Design Current”. Even with manual PBO settings and released EDC (you can set it to 1000A if you like) the CPU hardly will surpass it. And if it is, by a small margin. This is not allowed by the silicon controller. There is no way around that unless a static OC take place, and anything is possible. I don’t recommend...

Other PBO limits
PPT (Package Power Tracking =Total socket power draw)
TDC (Thermal Design Current)

TDC (90A) is irrelevant below temperature throttling threshold of 95C.

PPT for 3900X is 140W and it’s not easy to hit the value unless static OCed or in auto boosting under low temperatures. Around 70-75C will be around 135W. If you manage to cool it down, under 70C, EDC will also drop and will allow more clock and voltage and it may hit the 140W PPT limit.

If you uncap PPT with manual PBO settings (like 145W) it will pass 140W if EDC and temp is allow this.

If you cap EDC to 135A or 130A or even more then the PPT will almost certainly surpass the 140W (with more clock/voltage) as long as you give it headroom by setting it 145W or 150W. Again, temperature must allow this.

More or less this is the function of ZEN2 silicon FITness controller.


----------



## mtcn77 (Jan 23, 2020)

tabascosauz said:


> Stock EDC (short-term) limit is 140A; PBO won't take his chip far past that, you have to run fixed freq for that. And like I've said a billion times, fixed freq is not the way to go.


Sounds like you have found a way to cool 7nm density before having overclocked it to the limit.


----------



## tabascosauz (Jan 23, 2020)

mtcn77 said:


> Sounds like you have found a way to cool 7nm density before having overclocked it to the limit.



Sounds like you haven't read the thread. "I don't plan on hardcore OCing, but I will probably flip on PBO."

PBO isn't going to hit 200A.


----------



## mtcn77 (Jan 23, 2020)

tabascosauz said:


> Sounds like you haven't read the thread. "I don't plan on hardcore OCing, but I will probably flip on PBO."
> 
> PBO isn't going to hit 200A.


Sounds like 200A will not trigger FIT a while earlier, /s.
EDC is the best 'power virus' management utility. It doesn't allow heat pockets to develop in the first place.
PS: if you are interrupting pbo, you must take preventive measures not to fiddle with fixed frequency performance. One is to keep FIT at bay.


----------



## terroralpha (Jan 24, 2020)

lexluthermiester said:


> I found 6 that meet the requirements stated in the OP.
> 
> 
> 
> ...



not true. the gigabyte board is not good enough. i have it (see attachment). it does not feed the CPU enough power. the 3900X _should_ score around 7100 in cinebench R20. on the gigabyte B450-i it gets between 6300 and 6800. always a random number. i thought my board was bad or the CPU was a dud. the CPU checks out fine in a low end lenovo desktop board with the same SSD* and RAM. the replacement gigabyte B450-i i got is equally worthless. does the same thing.

i also tried other benches and tried running an adobe premiere job. the gigabyte board comes up short every time. i started this thread specifically because the gigabyte B450-i that i have does not do what i need it to do.

those asrock boards are probably even worse. i've seen reviews of those boards, from both professionals and users, saying they gimp R7 CPUs. R9 need not apply. they both use the same worthless 3 phase VRM, with doublers, and terrible cooling.



back to the topic, thank you everyone for the input. there is some amazing in-depth information here. i learned more than i thought i would. i will go with the MSI board. i will only need 1 M.2 slot and don't care about the audio chipset. i will update this post to let you guys know how it handles the 3900X.


----------



## freeagent (Jan 24, 2020)

Lots of good info here, very educational.


----------



## Zach_01 (Jan 24, 2020)

terroralpha said:


> not true. the gigabyte board is not good enough. i have it (see attachment). it does not feed the CPU enough power. the 3900X _should_ score around 7100 in cinebench R20. on the gigabyte B450-i it gets between 6300 and 6800. always a random number. i thought my board was bad or the CPU was a dud. the CPU checks out fine in low end lenovo desktop board with the same memory and RAM. the replacement gigabyte B450-i i got is equally worthless. does the same thing.
> 
> i also tried other benches and tried running an adobe premiere job. the gigabyte board comes up short every time. i started this thread specifically because the gigabyte B450-i that i have does not do what i need it to do.
> 
> ...


3900X in some circumstances could reach 7300~7400 in R20.

Out of curiosity... what Lenovo board was that? Did you test it in the same case as the B450I Aorus?

To take it further, can you screenshot a HWiNFO sensors page during R20 run?

Like this where all info available/visible...


			https://www.techpowerup.com/forums/attachments/hwinfo_06_01_2020_99_60_63_x3_newpaste_cool-png.142511/
		


I’m interested in this kind of info, but at the same time I like to see if I can find anything else that could be wrong, other than board’s VRM.
Although 4 phases of 50A each isn’t good enough for a 140A CPU... That’s not hard to think.


----------



## terroralpha (Jan 24, 2020)

Zach_01 said:


> 3900X in some circumstances could reach 7300~7400 in R20.
> 
> Out of curiosity... what Lenovo board was that? Did you test it in the same case as the B450I Aorus?
> 
> ...



the B450-i was on a test bench. not in a case. but i used the same ssd and memory. the lenovo PC is a thinkcentre. can't remember the exact model. i'll get back to you on that. it originally came with a 2700X pro CPU. it's a regular, off the shelf office PC. nothing special. 

i'll try to get that HWinfo and post it here.


----------



## Zach_01 (Jan 24, 2020)

terroralpha said:


> the B450-i was on a test bench. not in a case. but i used the same ssd and memory. the lenovo PC is a thinkcentre. can't remember the exact model. i'll get back to you on that. it originally came with a 2700X pro CPU. it's a regular, off the shelf office PC. nothing special.
> 
> i'll try to get that HWinfo and post it here.


For the Lenovo board it’s not all that significant. The most I wanted to know was the test conditions and if it was the same, but as it turns out the B450-I test bench is better for thermals.


----------



## JackCarver (Jan 24, 2020)

terroralpha said:


> those asrock boards are probably even worse. i've seen reviews of those boards, from both professionals and users, saying they gimp R7 CPUs. R9 need not apply. they both use the same worthless 3 phase VRM, with doublers, and terrible cooling.



The Asrock VRM is crap...it has Onsemi discrete MOSFETS whereas MSI or Gigabyte use integrated power stages here. The efficiency and heat dissipation of those discrete MOSFETS is not as good as those of power stages. And as it has only 3 real phases, they do a twin arrangement of 3x2 phases to reduce load and heat on each phase. But also MSI use discrete MOSFETS on their X570 Gaming Plus or Gaming Edge Boards...not the best solution but cheap...
The next problem is output ripple which degenerates cpu over time and  which is worse with 3 real phases compared to 6 real phases.


----------



## lexluthermiester (Jan 24, 2020)

JackCarver said:


> The next problem is output ripple which degenerates cpu over time and which is worse with 3 real phases compared to 6 real phases.


This is absolute nonsense. Voltage ripple does not degrade CPU's unless excessive voltage is being applied, but then you have a much bigger problem.


----------



## JackCarver (Jan 24, 2020)

Sure, if you have 25mV ripple and you need for a stable oc 1.375V then you have to set 1.4V to get stable. So the Chip degrades at 1.4V but you only would need 1.375V.


----------



## lexluthermiester (Jan 24, 2020)

JackCarver said:


> Sure, if you have 25mV ripple


Most voltage ripple is measured in .005v increments..


JackCarver said:


> So the Chip degrades at 1.4V but you only would need 1.375V.


That depends on the voltage specs for the CPU's in question. 1.4v is not going to damage an AM4 CPU long term.


----------



## JackCarver (Jan 24, 2020)

That was only an example, with higher voltage the effect is still there.


----------



## lexluthermiester (Jan 24, 2020)

JackCarver said:


> That was only an example, with higher voltage the effect is still there.


Whether or not voltage ripple is present is not what I'm taking issue with. Voltage ripple ALWAYS exists because everyone in the world runs on AC power grids. What defines how great the effect is depends on the PSU and mobo quality. A solid PSU will make even a low quality board run well, where as a crap PSU will make even the best board run like crap.

The OP is not going to match a solid board to a crap PSU, so voltage ripple will not be an issue. And for the record, 3x2 phase power is electronically as a stable a 6x1. The VRM part quality is more important than that of the end configuration.


----------



## JackCarver (Jan 24, 2020)

The more phases you have the less the ripple effect, also the higher your pwm controller is switching the less the ripple effect or you have crap or good inductors may also be a point here. Why do oc mainboards have the Feature to adjust PWM switching frequency? One point is to reduce ripple.
A real 6 phase vrm is way better than a 3x2 or 3 phases doubled vrm.

Edit:
It depends not on the PSU and a solid PSU doesn‘t compensate a crap vrm in any way.


----------



## Chrispy_ (Jan 24, 2020)

I can confirm that PBO+ works fine with a 3900X using both an MSI B450M Mortar Max (2+2 phase) and Asrock B450 Pro (3x2 phase). Ryzen Master shows power draw of between 135 and 140W with my two samples.

These are both relatively low end boards for a 3900X but with half-decent VRM and proper heatsinks they don't seem to have any issues with PBO+

I'm not sure I'd be going for overclocking records with them but IMO there's really no point pumping huge amounts of juice into Zen2. It's 98% of the way there using stock voltages on PBO+ and whilst you can definitely push it higher than that, throwing silly amounts of voltage at them will get you a hundred MHz maybe, but an earful of fan noise and potentially short lifespan of the chip.


----------



## terroralpha (Jan 24, 2020)

Chrispy_ said:


> I can confirm that PBO+ works fine with a 3900X using both an MSI B450M Mortar Max (2+2 phase) and Asrock B450 Pro (3x2 phase). Ryzen Master shows power draw of between 135 and 140W with my two samples.
> 
> These are both relatively low end boards for a 3900X but with half-decent VRM and proper heatsinks they don't seem to have any issues with PBO+
> 
> I'm not sure I'd be going for overclocking records with them but IMO there's really no point pumping huge amounts of juice into Zen2. It's 98% of the way there using stock voltages on PBO+ and whilst you can definitely push it higher than that, throwing silly amounts of voltage at them will get you a hundred MHz maybe, but an earful of fan noise and potentially short lifespan of the chip.


Try running cinebench r20 Back to back a few times, let me know what score you get and if it’s consistent or not.


----------



## lexluthermiester (Jan 24, 2020)

terroralpha said:


> Try running cinebench r20 Back to back a few times, let me know what score you get and if it’s consistent or not.


You're sticking these parts into an ITX case, are you really going to be stressing it that much?


----------



## JackCarver (Jan 25, 2020)

If one of these boards then take the Mortar, stay away from the Asrock. The Mortar has 4 phases and 2 Low/High Side MOSFETs per phase, each capable of 80A max. They have also less resistance.
The Asrock only 3 phases, twin arrangement, with 2 Low/High Side MOSFETs per phase, each capable of 65A max and higher resistance, so MSI should stay cooler here.


----------



## freeagent (Jan 25, 2020)

Crank up voltage and LLC, move some air over VRMs and let er rip. .  It only gets warm if you let it  Guys are saying it runs, kick it in the nuts it'll do something for awhile. If you want to want to run your overclocks 24/7 you should be buying a good board anyways to run those overclocks.


----------



## terroralpha (Jan 25, 2020)

lexluthermiester said:


> You're sticking these parts into an ITX case, are you really going to be stressing it that much?



if the motherboard buckles under stress from a 10 second benchmark, then it will not last long. this is a complicated build and if i have to take it apart one more time i might just flip out.


----------



## lexluthermiester (Jan 25, 2020)

JackCarver said:


> If one of these boards then take the Mortar, stay away from the Asrock. The Mortar has 4 phases and 2 Low/High Side MOSFETs per phase, each capable of 80A max. They have also less resistance.
> The Asrock only 3 phases, twin arrangement, with 2 Low/High Side MOSFETs per phase, each capable of 65A max and higher resistance, so MSI should stay cooler here.


Your opinions are high subjective. The MSI has a much older audio chipset.



terroralpha said:


> if the motherboard buckles under stress from a 10 second benchmark, then it will not last long. this is a complicated build and if i have to take it apart one more time i might just flip out.


Fair enough.


----------



## NoJuan999 (Jan 25, 2020)

I have an AsusROG Strix B450-F (4 phase) and an Asus ROG Strix X470-F (6 phase) and they both worked very well with my 3700x.
And from the info I found here:


			https://docs.google.com/spreadsheets/d/1wmsTYK9Z3-jUX5LGRoFnsZYZiW1pfiDZnKCjaXyzd1o/htmlview?sle=true#gid=2112472504
		









						AM4 B450/X470 Motherboard Vcore VRM Tier List v1.3
					

B450/X470 v1.3                                                   AM4 B450/X470 MOTHERBOARD Vcore VRM TIER LIST v1.3 (2019-03-29),                  BY Cautilus#5912 (Discord)                         Cr1318 (Reddit) ASROCK,ASUS,GIGABYTE,MSI TOP TIER Most suitable for extreme overclocking,X470 Taich...




					docs.google.com
				




The B450-I and X450-I and both a step above the B450-F and a slight step down from my X470-F as far as VMs go so either should run the 3900x just fine with PBO set on auto and decent case airflow.


----------



## JackCarver (Jan 25, 2020)

lexluthermiester said:


> Your opinions are high subjective. The MSI has a much old audio chipset.



Ok, that could be true, didn't look for other components of those mainbaords as OP asks a vrm question.



NoJuan999 said:


> The B450-I and X450-I and both a step above the B450-F and a slight step down from my X470-F as far as VMs go so either should run the 3900x just fine with PBO set on auto and decent case airflow.



The Asus X470 and the MSI B450I should be vrm wise nearly the same, the Asus has a slightly better SOC vrm as far as I can see. As he looks for an ITX board I woulod recommend the MSI.


----------



## TheMadDutchDude (Jan 25, 2020)

JackCarver said:


> VRM wise the MSI B450I Gaming is the best.


Based on what proof, exactly?


----------



## JackCarver (Jan 25, 2020)

TheMadDutchDude said:


> Based on what proof, exactly?



Yes look on the VRM Tier list nojuan999 posted a little before. There you can see it right at the top and all mainboards lexluthermiester posted are below that. Or look for the technical details of the used power stages and you will find it also...


----------



## lexluthermiester (Jan 25, 2020)

JackCarver said:


> Yes look on the VRM Tier list nojuan999 posted a little before. There you can see it right at the top and all mainboards lexluthermiester posted are below that. Or look for the technical details of the used power stages and you will find it also...


You're not proving your point. That list was made by some dude who is not what can be considered a credible source. All you're doing is expressing opinion without any merit. The OP asked for ITX motherboards which meet certain requirements. All of the boards presented, regardless of your opinions, meet stated requirements and are built by well known and well regarded companies who have strict QA standards. Every one of them support the 3900X and will do so readily.


----------



## Countryside (Jan 27, 2020)

You can go into detail about different VRMs but usually its simple if the motherboard manufacturer has the the cpu in their CPU Support List then it will work.


----------



## EarthDog (Jan 27, 2020)

Countryside said:


> You can go into detail about different VRMs but usually it simple if the motherboard manufacturer has the the cpu in their CPU Support List then it will work.


Yes and No. History,  years of AMD FX and throttling at stock speeds with many boards, tells us otherwise. We've see it with Ryzen/R2/R3 already with budget and old chipset boards and big chips. Works and works properly are two distinct things. That said, it isn't all about phase count either... the bits below matter!!!

I'm not saying anything about the board chosen or whatnot, but just this blanket statement above.


----------



## Countryside (Jan 27, 2020)

EarthDog said:


> Yes and No. History,  years of AMD FX and throttling at stock speeds with many boards, tells us otherwise. We've see it with Ryzen/R2/R3 already with budget and old chipset boards and big chips. Works and works properly are two distinct things. That said, it isn't all about phase count either... the bits below matter!!!
> 
> I'm not saying anything about the board chosen or whatnot, but just this blanket statement above.



No manufacturer is perfect and you can find specific problems on all of them. The support list is there for a reason as for my so called blanket statement it comes in two parts the first one witch you anwserd and the second one you ignored.


----------



## terroralpha (Jan 28, 2020)

TheMadDutchDude said:


> Based on what proof, exactly?


Based on the VRM. The VRM itself is the proof. 6x 60amp phases on
6 true phases. The VRMs are also cooled, unlike the 6 fake VRMs on as rock boards.


----------



## Assimilator (Jan 29, 2020)

tabascosauz said:


> I'll never opt for for a board that places an NVMe M.2 on the back of the board (the MSI ITX).



May I ask why not?


----------



## tabascosauz (Jan 29, 2020)

Assimilator said:


> May I ask why not?



The NVMes can heat up quite a bit in confined spaces. Take my M1 for example; there's no room behind the board even if there is a cutout for the drive, since that side of the case doesn't have any clearance between the back of the mobo tray and the removable aluminium panel. The flash might like it hot, but the controllers don't.

The solution in a conventional case is to use a M.2 heatsink, but that still needs airflow, and in cases like the Node 202 and SG05/13 I just really don't see it being a good idea long term.

If there's something that the Aorus board does well, it's the combined PCH and M.2 heatsink. I've built twice with this board and it's handled SATA M.2 and NVMe M.2 excellently.


----------



## EarthDog (Jan 29, 2020)

SATA M.2 doesn't typically need additional cooling.

That said, unless you really have a heater and sustain writes, it isn't a huge issue...

... I get your point though.


----------



## Assimilator (Jan 29, 2020)

tabascosauz said:


> The NVMes can heat up quite a bit in confined spaces. Take my M1 for example; there's no room behind the board even if there is a cutout for the drive, since that side of the case doesn't have any clearance between the back of the mobo tray and the removable aluminium panel. The flash might like it hot, but the controllers don't.
> 
> The solution in a conventional case is to use a M.2 heatsink, but that still needs airflow, and in cases like the Node 202 and SG05/13 I just really don't see it being a good idea long term.
> 
> If there's something that the Aorus board does well, it's the combined PCH and M.2 heatsink. I've built twice with this board and it's handled SATA M.2 and NVMe M.2 excellently.



Fair enough, you're talking about extremely confined cases.


----------



## Zach_01 (Jan 29, 2020)

NVMe drives need air flow...
I just did some quick test.

I have no case and so I have a case fan (120mm 750~850rpm) upon VRM and around socket that blows air to NVMe drive also. X570 AorusPro has first m.2 slot above GPU and next to VRM/CPU socket and has a "heatsink" also.
With the fan on, temp of drive is around 32~34C. I removed the fan, keep broswing and check it 15mins later. Drive temp was climped to 46C and it was slowly still increasing. And it wasnt even doing anything serious. m.2 slot heatsink was warm enough...

SATA m.2 drives would be a different story... but NVMe need air flow.


----------



## lexluthermiester (Jan 30, 2020)

Fleurgris said:


> Those are the only two 4xx series boards i'm looking at. going to avoid asrock like the plague this time around due to their junk VRM.


That is an opinion. Not a very good one. You too are referencing a list made by some dude who has no credibility. There are no testing sources or methods listed, no evidence or information that proves any conclusion.


----------



## terroralpha (Jan 30, 2020)

the plot thickens. turns out that my 650W gold seasonic SFX PSU was a dud, it was not able to provide adequate power but at the same time wasn't shutting off either. the gigabyte B450 ITX board works fine with the 3900X. after i got a corsair SF750 PSU (on sale for $145 at amazon germany), that 3900X is hitting 7000+ in cinebench R20 consistently and without fail. adobe premiere render times are now consistent on every run. the CPU is no longer s**ing its' pants.

this is my second, back to back, bad seasonic experience. my main desktop use to have a seasonic 1000W "prime ultra" titanium PSU. it also had trouble delivering power and sometimes would cause my computer to turn on by itself in the middle of the night. dead giveaway that something was wrong with it. 

case closed. thanks for all your input guys. also, no more seasonic for me.



lexluthermiester said:


> That is an opinion. Not a very good one. You too are referencing a list made by some dude who has no credibility. There are no testing sources or methods listed, no evidence or information that proves any conclusion.


6 low quality power phases running on a 3 phase controller with no doublers. the phases were just hooked up in parallel. that means no load/heat balancing. and the cherry on top is that the phases are not cooled well at all.

if you are running a stock 8 core or smaller CPU, it's probably fine. if you want to OC said 8 core CPU on it or run 12 or 16 core CPU on it, that board will not work well. it probably won't die but it will throttle like crazy to prevent its' own death.


----------



## Adam Krazispeed (Jan 30, 2020)

i have the gigabyte I x570 aorus pro wifi (ITX) ( yeah its x570& has a fan) but my system runs with stock prism cooler with 3900x and no issues...
but you have upgradabiltiy to Gen4 GPUs and SSDs, you think Nvidias RTX 3000 AMPEARE isnt goinna be 4.0?//

and it is a full 8 phase vrm









						X570 I AORUS PRO WIFI (rev. 1.0) Key Features | Motherboard - GIGABYTE U.S.A.
					

Lasting Quality from GIGABYTE.GIGABYTE Ultra Durable™ motherboards bring together a unique blend of features and technologies that offer users the absolute ...




					www.gigabyte.com
				




best board for the money imo


----------



## terroralpha (Jan 30, 2020)

Adam Krazispeed said:


> i have the gigabyte I x570 aorus pro wifi (ITX) ( yeah its x570& has a fan) but my system runs with stock prism cooler with 3900x and no issues...
> but you have upgradabiltiy to Gen4 GPUs and SSDs, you think Nvidias RTX 3000 AMPEARE isnt goinna be 4.0?//


it turned out that my issue was the PSU, not the board. the gigabyte B450 can run PCI E 4 as well if you use an older BIOS. i'm running and MSI E 4.0 SSD on it now. the PCI E slot is also capable of PCI E 4 on this board. 

having said that, i would give up PCI-E 4 to not have a fan in a heart beat.


----------



## Zach_01 (Jan 30, 2020)

terroralpha said:


> the plot thickens. turns out that my 650W gold seasonic SFX PSU was a dud, it was not able to provide adequate power but at the same time wasn't shutting off either. the gigabyte B450 ITX board works fine with the 3900X. after i got a corsair SF750 PSU (on sale for $145 at amazon germany), that 3900X is hitting 7000+ in cinebench R20 consistently and without fail. adobe premiere render times are now consistent on every run. the CPU is no longer s**ing its' pants.


Thats very nice to hear!
Do you think you can provide a HWiNFO screenshot during R20 run now. I was interested and hoping to see one with the old PSU also (that is when you had the issue), but thats ok...
Like this




And one with idling/browsing...(30 min)



Are you not running latest BIOS for your board? You should if not...

1. latest BIOS (AGESA 1.0.0.4 B)
2. latest chipset drivers straight from AMD (not board vendor)
3. Win10 v1909
4. 1usmus universal power plan for Ryzen

...for best boosting (all core), and optimal core loading (single threaded and low/middle loads)

IMO the X570 chipset fan "issue" is exaggerated. Mine never spins, but I have a case fan (750~850rpm) next to it, no case. When I test it, was silent enough even at 2-3000rpm. But now doesnt matter, the GPU has completely cover it, and you can see temp in those screenshots hovering around 40C.


----------



## Sashleycat (Jan 30, 2020)

I just wanna say, I've taken an 1800X to 4.1 (1.4V) on an MSI B350 PC MATE before (4-phase) with a fan on the VRM heatsink. That was using over 200W in stress, the board took it like a champ. Now, I'm not saying that I recommend you do that, especially if you're planning on doing long-term work, but good airflow on the VRM heatsink/spreader really makes the difference.

I have my 3950X on Asrock X570M Pro4. This board isn't known for a Stellar VRM, but it's doing just fine (though I limit PPT to 105W sustained & have plenty of airflow).

If you had to ask me, I'd say the 3900X would be fine on even a budget B450 if you had good airflow & wasn't in the habit of pumping him at 100% load 24/7. Small ITX case? Probably not such a good idea. Anyway YMMV. I love PBO because I can configure the power usage (and thus thermal stress on the VRM) of the processor on the fly. You could do something similar with the 3900X, it's intelligent enough to maintain aggressive boost clocks in lightly threaded, bursty workload, but if you load up all 24 threads; it'll reign in the power usage. 3900X and 3950X are 146W PPT afaik. 



Zach_01 said:


> IMO the X570 chipset fan "issue" is exaggerated. Mine never spins, but I have a case fan (750~850rpm) next to it, no case. When I test it, was silent enough even at 2-3000rpm. But now doesnt matter, the GPU has completely cover it, and you can see temp in those screenshots hovering around 40C.



I agree, but I wouldn't hear mine even at 5K on account of the 3x 3000 RPM 140MM PPCs lol. I'm in the minority when I say fan noise is comforting to me? Probably an Autism thing. :/



Adam Krazispeed said:


> you think Nvidias RTX 3000 AMPEARE isnt goinna be 4.0?//


It will likely be 4.0. But whether it benefits in gaming from that, is another story entirely.


----------



## lexluthermiester (Jan 30, 2020)

terroralpha said:


> the phases were just hooked up in parallel.


Even if true, which is doubtful, there's nothing wrong with that electrically and electronically.


terroralpha said:


> that means no load/heat balancing.


And how do you reach that conclusion?


terroralpha said:


> and the cherry on top is that the phases are not cooled well at all.


That's just flat out wrong. Every one of those boards have heatsinks on the VRM's

However, you solved your problem with your existing board and a new PSU.


----------



## ShrimpBrime (Jan 30, 2020)

Sashleycat said:


> I just wanna say, I've taken an 1800X to 4.1 (1.4V) on an MSI B350 PC MATE before (4-phase) with a fan on the VRM heatsink. That was using over 200W in stress, the board took it like a champ. Now, I'm not saying that I recommend you do that, especially if you're planning on doing long-term work, but good airflow on the VRM heatsink/spreader really makes the difference.
> 
> I have my 3950X on Asrock X570M Pro4. This board isn't known for a Stellar VRM, but it's doing just fine (though I limit PPT to 105W sustained & have plenty of airflow).
> 
> ...



Its fun to watch the convo. Lots of different opinions here. 
Some facts which is good and some skewing from the topic. No probs.

Id pit my Asus Rog B450-I to a 3900X test while is has IR3553 on 6 phases. 

The issue is we are advertised 105w. This wattage is only accurate to the highest p-state of the cpu under a full load.

While all of us will see higher wattage usage while using even defaul PBO.

But Id pit my Asus Rog B450-I to the test running a 3900x. 
6 IR3553 VRMs on 6 phase would be plenty even if you could manage to pull 200w. 

Then cooling.
Well if you're not scared to run your cpu at 85c, why would it bother one to see VRMs getting that warm? Most VRMs operate at 100c as thats the design. Wont hurt it. Cool it? Yes you should. Some of that heat makes its way through the board right to the cpu and visa versa.

3900x. 6 vrms. Meh why not. This is no FX 220w cpu. Should be no issue for any one.


----------



## Sashleycat (Jan 30, 2020)

ShrimpBrime said:


> The issue is we are advertised 105w. This wattage is only accurate to the highest p-state of the cpu under a full load.
> 
> While all of us will see higher wattage usage while using even defaul PBO.


105W is the TDP, not the power consumption though?. While broadly related, they are not =.

AFAIK for Ryzen it is:

45W TDP = 60W PPT (socket power)
65W TDP = 88W PPT
95W TDP = 125W PPT
105W TDP = 146W PPT

With 3rd gen parts, all of the SKU seem to be at, or close to, their PPT limits while the previous gen (in my experience) are closer to "TDP".

Anyway, 100C VRM is fine for the MosFETs, yes, but my main concern was actually Aluminum electrolytic capacitors around the VRM/socket, which really don't appreciate high temps and can be problematic if they're in an airflow dead-zone. Anyway, YMMV, my standards are pretty high because I need my systems to run 24/7 at 100% load.


----------



## ShrimpBrime (Jan 30, 2020)

Sashleycat said:


> 105W is the TDP, not the power consumption though?. While broadly related, they are not =.
> 
> AFAIK for Ryzen it is:
> 
> ...



But we run around like boards are failing 105w 146w ppt on 4+1, which you actually don't really see happenening much. At least I havent read about many boards VRM failing.

105w is a Thermal design power. 146w is energy usage. 

Not really sure what the concerns are.... People run 105w chips on 4 VRMs a lot more often than on boards with 6 VRMs.

I only find the conversation curious, while these chips run pretty cool and use quite a bit less PPT than previous generations. And they where supporting 125w chips on 4 VRMs then..... We all had the same convo then as we do now.

Again, Id pit my 6 VRMs to a 3900x, but Im well aware of how  to cool my hardware.


----------



## Sashleycat (Jan 30, 2020)

ShrimpBrime said:


> But we run around like boards are failing 105w 146w ppt on 4+1, which you actually don't really see happenening much. At least I havent read about many boards VRM failing.
> 
> 105w is a Thermal design power. 146w is energy usage.
> 
> ...


I agree tbh, the VRM argument is a bit over-exaggerated. Gigabyte actually 'certified' their Heatsink-less B350 D3V with 4 phases for the 3950X on the latest bios. (DISCLAIMER: Don't use this board with a 3950X, the VRM would throttle it a LOT). People seem to think that motherboards are going to explode into flames if they draw a bit more power. In reality, most of these boards are going to trigger PROCHOT EXT and throttle the CPU (it might not even be by a lot). If Gigabyte certified that, then they are OK with using 3950X on it for warranty period.

Most B450 boards (maybe all) are perfectly adequate for 3800X for full use, and 3900X and 3950X for use with reasonable airflow if you don't want throttling.


----------



## EarthDog (Jan 30, 2020)

I dont think a tone said they will explode...but the point is to be careful. If you are buying a HCC chip, it makes sense to pair it with a more robust vrm so you can get the most out of it (read: no throttling, better chance to achieve rated boost...and for longer, etc). 

Just because a HCC chip is on the compatibility list it will work 'properly' isn't The Gospel. We've seen issues like this from the same company a couple gens ago. Shrimp knows... hes an fx guy. Many boards couldnt handle the 'octo' fx without throttling or having to resort to mods/active cooling to prevent throttling. We see x570 is, overall, a more robust vrm platform and for good reason. There are plenty of x470 boards that can do it.. but once you get to b450 on down, id be a bit leary especially if I wanted the most out of the cpu.


----------



## JackCarver (Jan 30, 2020)

terroralpha said:


> it turned out that my issue was the PSU, not the board.



Nice that you found the problem in your case 



lexluthermiester said:


> That is an opinion. Not a very good one. You too are referencing a list made by some dude who has no credibility.



Yes and that is also an opinion or did you prove that this list is wrong? It's easy to request proof from others but not providing any by yourself.

Actually I didn't claim, that one of the posted boards is not able to run a Ryzen 3900X. I only gave some advice which of these boards, in question their VRMs, is more or less capable to run a Ryzen 3900X.
Sure every board which has the Ryzen 3900X on its support list will run this CPU, no question at all, but the other question is, on which of these boards will it run better or let's say does it has more headroom. And regarding this point everyone can prove this statement.

1, Regarding number of phases:
The VRM must be capable of handling the current load. That can be done with any of those solutions out there. You can do it via fake phases, that is every phase has its components twice, or even three times like Asus did in their latest X570 boards, or you can do it via doublers or do it with real phases. All of these solutions make the VRM capable of handling more current and not getting too hot. But current handling is only one problem here. Another is a smooth voltage output and less ripple. This problem cannot be solved with twin, triple or doubled phases but with a higher number of real phases or with a higher switching PWM controller. As higher switching decreases the efficiency of the VRM the solution to add more phases is better here. So ideally your VRM has for example an 8-phase capable PWM controller and you have 8 real phases. If one of those phases are discharging another of the 8 can set in with an offset and voltage drop gets smoothed. With 4 fake phases or even less and twice components there are only 4 or 3 in the game of charging/discharging and with 4 doubled phases, the PWM switching freq gets halved which downgrades voltage output also and makes transient response worse.
But if your VRM is too oversized for the daily load, the efficiency will also be a little worse. So it has to match the used cpu and if you are planning to oc, but we are talking here of an Ryzen 3900X, so not the smallest AMD cpu.

2, Regarding the used MOSFETs
Every VRM consists of High-Side and Low-Side MOSFETs and they both have a specific max current capability. Some boards have separate chips other boards have one chip as package of High/Low-Side MOSFET included, others include also the Gate Driver. Each MOSFET High/Low-Side has to handle a portion of the current load. How much determines the duty cycle of the PWM signal. The smaller the duty cycle the more current have to handle the Low-Side MOSFETs. As the duty cycle calculates to Vout/Vin you see that the less the cpu output voltage for a given input voltage is the smaller is the duty cycle and the more current have to handle the Low-Side MOSFETs. So they must be the better chips in the VRM or those chips that have the better current capability compared to the High-Side MOSFETs. So you can approximately calculate the VRMs current capability in counting the number of Low-Side FETs and multiply it with their current capability.
Additionally the power losses in the MOSFETs result in increasing temps. Power Losses are mainly conduction losses and switching losses. First is dependent of the MOSFETs Drain to Source resistance, can be found in their data sheets, second depends of the switching freq. Both result in increasing temps and the amount of heat, the MOSFET rises per W power loss, depends of the MOSFETs thermal resistance, can alo be found in their data sheets. The hotter the MOSFET the less its current handling capability.
So the less Drain to Source resistance, the less thermal resistance and the less switching loss, the less heat is produced and the better the efficiency and current capability.

3, The Boards
If you look for example at these posted boards:
- Asrock Fatality B450 Gaming ITX
- Asrock Fatality X470 Gaming ITX
- Gigabyte B450I Aorus
- Asus ROG STRIX B450-I Gaming
- Asus ROG STRIX X470-I Gaming
- MSI B450-I Gaming Plus

*The Asrock boards*:
Both have 6 fake phases, that is only 3 real phases and every of these 3 phases has its components twice. According to a list from Hardwareluxx, the B450 Gaming uses for High/Low-Side MOSFETs either the Onsemi FDPC5030 or the Sinopower SM7341EH . I think this is dependent of the board's revision. Assuming they use both the Onsemi chip, this chip consists of one package with High-Side and Low Side MOSFET included. Here is the data sheet:



			https://www.onsemi.com/pub/Collateral/FDPC5030SG-D.PDF
		


The Ryzen 3900X draws 100A to 140A (Spikes) with stock setting, no oc here. At 100A every stage (3x2)  has to handle 100/6=16,7A. With spikes up to 140/6=23.3A. With the data from the data sheet you can calculate the power losses in the MOSFETs (mainly conduction losses, switching losses and charging losses) to approximately (assuming 12V input/1.42V output, 300kHz switching freq):
Power Loss@16,7A=1.14W
Power Loss@23,3A=2.1W

According the data sheet, the chip has a thermal resistance junction to ambient of 55 degrees C/W, that is 1W power loss in the MOSFET results in 55 degrees celsius heat against ambient. So if ambient is about 25 degrees the junction temp will result in 25+55=80 degrees celsius.

1.14W power loss corresponds to 1.14x55=62.7C
2.1W power loss results in 2.1x55=115.5C

At an ambient of 25 degrees it will result in the first case to 62.7+25=87.7C and in the second case to 115.5+25=140.5C junction temp. The max junction temp of this chip is 150 degrees, so a heatsink is definitelyx needed to cool the MOSFETs down.

*The Gigabyte B450I Aorus:*
Gigabyte uses 4 real phases with IR3556 stages. The IR is a package with Low and High Side MOSFET and gate driver included. It's a 50A stage and as they don't use doubled or twin phases each phase has to handle 100/4=25A up to 140/4=35A.



			https://www.infineon.com/dgdl/ir3551.pdf?fileId=5546d462533600a4015355cd84a11763
		






Fortunately they have a power loss graph of the IR3551 as there is no data sheet of the 3556, but both are IR 50A stages.
The thermal resistance junction to ambient is here 21.1 C/W, that's way better than the Asrock stages thermal resistance. The power loss at 25A is at approximately 2.5W, so at 25 degrees ambient it would result in 2.5x21.1+25=77.75 degrees junction temp.
The power loss at 35A is at 4.5W, so 4.5x21.1+25=119.95C degrees junction temp. So although it only uses 4 power stages here it stays cooler than the two Asrock boards because of the thermal resistance of the used IR stages. Additional those IR stages have the Gate Driver included, which dissipates additional power loss, so they are very efficient.

*The Asus B450I Gaming board:*
6 real phases of IR3556 stages, the same Gigabyte uses but now 2 more. Each phase has to handle 16.7A up to 23.3A, the same as Asrock here.
Power loss at 16.7A at about 1.6W result in 1.6x21.1+25=58.76 degreees junction. Power loss at 23.3A approx 2.3W result in 2.3*21.1+25=73.53 degrees junction temp, so the best far now.

*The Asus X470 board:*
The same VRM as the B450I board.

*The MSI B450I Gaming:*
6 real phases of IR3555 power stages. Those are 60A power stages.





As there is no data sheet of the IR3555 here is one of the IR3550, also a 60A IR stage:



			https://www.infineon.com/dgdl/ir3550.pdf?fileId=5546d462533600a4015355cd7c831761
		


Thermal resistance junction to ambient is here 20.2 C/W. The power loss at 16.7A is at approx 1.3W results in 1.3x20.2+25=51.26 degrees junction temp. Power Loss at 23.3A is at 2W, results in 2x20.2+25=65.4 degrees junction.


All those temps are without heatsink, the chips mounted on a 1 in2 pad of 2 oz copper, as stated in their data sheets to get it comaprable. With heatsinks all of these boards are capable to handle a stock Ryzen 3900X, but nevertheless you can make a rating which VRM will be more or less capable or efficient, and this is my personal rating from top to bottom:

1, MSI B450I Gaming
2, The two Asus boards
3, The Gigabyte board
4, The two Asrock boards

And I would stay away from the Asrock boards if I had to choose a new B450/X470 board and if I have a Ryzen 3900X/3950X to put in. If I would own such a board already it will do fine also, no question, but with less headroom than the others.


----------



## lexluthermiester (Jan 30, 2020)

@JackCarver
That was an impressive, very technical display. If the OP had not already stated that the problem was their PSU and not the motherboard, I would be happy to discuss your presentation.


----------



## Otonel88 (Jan 30, 2020)

Even the MSI B450 Tomahwak can handle the 3950x according to HardwareUnboxed which is a beast of a processor.
The only thing that I don't like about that board it's somehow the astethics (it doesnt have some fancy vram, back inputs cover), and in some areas it can lack some features, but other than that everyone says it's a good board. Is the board would be a bit more aesthetically pleasing and a few more features for £150 it would be great.


----------



## ShrimpBrime (Jan 30, 2020)

lexluthermiester said:


> @JackCarver
> That was an impressive, very technical display. If the OP had not already stated that the problem was their PSU and not the motherboard, I would be happy to discuss your presentation.



It's relevant, please discuss!! 



Otonel88 said:


> Even the MSI B450 Tomahwak can handle the 3950x according to HardwareUnboxed which is a beast of a processor.
> The only thing that I don't like about that board it's somehow the astethics (it doesnt have some fancy vram, back inputs cover), and in some areas it can lack some features, but other than that everyone says it's a good board. Is the board would be a bit more aesthetically pleasing and a few more features for £150 it would be great.



I wouldn't run a Phenom on an MSI board.... Oh wait that one got RMA'ed 3 times and never again. I wouldn't put a 3900 anything in any MSI board unless it was top tier. Opinion only, I'm an Asus guy.


----------



## terroralpha (Jan 30, 2020)

ShrimpBrime said:


> I wouldn't run a Phenom on an MSI board.... Oh wait that one got RMA'ed 3 times and never again. I wouldn't put a 3900 anything in any MSI board unless it was top tier. Opinion only, I'm an Asus guy.



we all have our horror stories. when the original threadripper came out, i first got an asus zenith extreme, a $600+ board at the time. i went through 4 of them. not a single one of them worked right. they all have stupid problems. eventually replaced it with an asrock board and everything started working fine.


----------



## ShrimpBrime (Jan 31, 2020)

terroralpha said:


> we all have our horror stories. when the original threadripper came out, i first got an asus zenith extreme, a $600+ board at the time. i went through 4 of them. not a single one of them worked right. they all have stupid problems. eventually replaced it with an asrock board and everything started working fine.



Ive read several stories about that board zenith. Unfortunate for that looks like a top board too. 
I like MSI video cards though. The boards Im not fond of the bios. 
Had issues with AsRock once also. Z77 extreme 4. Lost memory channels. Turned out it was a known issue I didnt know about when I purchased it. 
Asus, Ive kill a couple of boards. Killed a couple bios chips. 
Biostar.... Everyone of them Ive touched died from overclocking ( a couple few) had a Dual sata 2 s939 that you could get a riser card and upgrade to Am2. Well I killed an FX-55 and the board with a bad volt mod lol.....

I think most boards fail from my abuse more so that just failing in general, but theres been a coulple times in the past, the board just died on its own.

Its one of the worst feelings in the world to break expensive hardware, that's all I know lol.


----------



## JackCarver (Jan 31, 2020)

I have a MSI Z370 Gaming Pro Carbon. It's ok but with really high load on my Core i7 8700K@5 GHz the VRM begins to throttle the CPU at about 10 min OCCT AVX512 with small dataset. CPU temps are fine at 70 degrees watercooled, but the VRM heatsink isn't able to cool appropriate. Would need active VRM cooling here or increase the AVX offset from -2 to -3 or even higher to get OCCT for longer stable but it happens only in this case.


----------

