# PSU for a new build



## AusWolf (Oct 13, 2020)

Hi all,

I'm planning on a new build, and there's one thing I'm not sure of, and that's the PSU. The build I'm planning is this, or similar:

Any good B550 microATX board - my current candidate is the *ASUS B550M TUF Gaming WiFi*
*Ryzen 9 5950X* CPU with a 240 mm AIO watercooler - probably some version of the Corsair H100i or the Arctic Liquid Freezer II
*2x 16 GB* Corsair Dominator 3200 MHz DDR4 kit
*Radeon RX 6900 XT* or *GeForce RTX 3070* Ti 16 GB if it ever comes into existence
I already have a SATA SSD and a 5400 RPM laptop HDD which are fine for the time being - might upgrade to nvme later
My only dilemma is the PSU: I already have a Seasonic Prime Ultra Platinum 550 W. If it was any other, cheaper 550 W unit, I'd say it's a complete no-go, but this one is the best quality PSU I've ever had, and unlike some cheap ones, it should have no trouble delivering the promised 550 watts. It's fairly new as well, so I really don't want to buy another one if I don't absolutely have to. What would you guys do? Should I go ahead with the build and hope for the best? Or should I invest in a larger PSU even if I have to skimp on a part or two as a result?

Thanks.


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## dgianstefani (Oct 13, 2020)

You don't need to replace the PSU


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## Rei (Oct 13, 2020)

dgianstefani said:


> You don't need to replace the PSU


Agree to this. But, if you're gonna upgrade down the line to something higher than 3080 level & you have lots of USB & other peripherals connected then this PSU might be a close shave but still enough.
Just wondering, how much did that PSU cost?


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## kiriakost (Oct 13, 2020)

At the past decade the choices was much simpler.  
All products they had sticker with power consumption. 
In the SUM you were add 30% of extra watts and you had a successful watt sizing calculation. 

Nowadays I do follow my own rule of the thumb,  750W in anything,  this add life cycle extension measured in years, the PSU it will run cooler, the fan noise will be minimum all times.
Good luck.


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## AusWolf (Oct 13, 2020)

Rei said:


> Agree to this. But, if you're gonna upgrade down the line to something higher than 3080 level & you have lots of USB & other peripherals connected then this PSU might be a close shave but still enough.
> Just wondering, how much did that PSU cost?


Thank you both. 

It was a little over the £100 mark. A bit expensive for this wattage, but it was well worth it at the time (after all the rubbish PSUs I've had).



kiriakost said:


> At the past decade the choices was much simpler.
> All products they had sticker with power consumption.
> In the SUM you were add 30% of extra watts and you had a successful watt sizing calculation.
> 
> ...


Makes sense. 

I might swap for a larger unit in the not so near future, but as long as it does the job _now, _with the build I'm currently planning, I'm happy.


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## xman2007 (Oct 13, 2020)

Both will likely be close to 300w gpu's, the 5950x whilst having a 105w tdp could well consume 180w+ at full tilt so you're nearly at 500w for just the cpu and gpu, whilst it's a damn fine 550w I really think you need 650-750w for this build.


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## dirtyferret (Oct 13, 2020)

AusWolf said:


> Hi all,
> 
> I'm planning on a new build, and there's one thing I'm not sure of, and that's the PSU. The build I'm planning is this, or similar:
> 
> ...


1. the current PSU is excellent and as you stated shows no issues
2. the 5950x, 6900XT & RTX 3070ti have all yet to be released and tested so how can you plan to run something without first knowing what you need to run it?


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## AusWolf (Oct 13, 2020)

dirtyferret said:


> 1. the current PSU is excellent and as you stated shows no issues
> 2. the 5950x, 6900XT & RTX 3070ti have all yet to be released and tested so how can you plan to run something without first knowing what you need to run it?


1. Thanks. I hope this stands with the next build as well. 
2. I'm just trying to plan ahead based on initial estimates and announcements to avoid unpleasant surprises. I could have said 3950X with an RTX 3080, but with TDP limits on basically everything nowadays, I'm not sure how much difference it would've made.


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## Selaya (Oct 13, 2020)

Have a look at this:








						AMD Ryzen 9 3900XT Review
					

The Ryzen 9 3900XT is the flagship of the new AMD Ryzen XT series. It comes with higher boost clocks and can sustain them better, which helps with single-threaded workloads. In our Ryzen 9 3900XT review, we also saw better overclocking and lower temperatures than on the original Ryzen 9 3900X.




					www.techpowerup.com
				




Specifically:






It is very unlikely both the CPU and GPU will both draw maximum power at the same time, most if not all games will not fully load the CPU.


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## ratirt (Oct 13, 2020)

dirtyferret said:


> 1. the current PSU is excellent and as you stated shows no issues
> 2. the 5950x, 6900XT & RTX 3070ti have all yet to be released and tested so how can you plan to run something without first knowing what you need to run it?


I wouldn't say, if it shows no issues then it's OK. The thing is, you don't want to wait till the PSU starts showing issues. I'd got safe spot 650W Seasonic and call it a day.  Also, the specs for the processor would be more like the 3950x is and the 3070Ti would definitely gobble 250W so 550W PSU might be a little short. Someone mentioned, the CPU and GPU will not be utilized by 100% (or close) at the same time. Well that depends. If you are planning on a live stream or do some work involving CPU and GPU working together at near max I wouldn't risk the 550Watt PSU no matter how expensive it is.
The other question about your current PSU is, how old is it?


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## dirtyferret (Oct 13, 2020)

AusWolf said:


> I'm just trying to plan ahead based on initial estimates and announcements to avoid unpleasant surprises.


nothing wrong with planning ahead just make sure you have something to plan with it.  One or more of those items can be a power hog or surprisingly efficient.  No one knows until someone gets their grubby little hands on them and tests them



AusWolf said:


> I could have said 3950X with an RTX 3080, but with TDP limits on basically everything nowadays, I'm not sure how much difference it would've made.


You could have but then you are just building for two items you don't plan to buy...so that doesn't answer your question just answers what you need for those items.


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## AusWolf (Oct 13, 2020)

ratirt said:


> I wouldn't say, if it shows no issues then it's OK. The thing is, you don't want to wait till the PSU starts showing issues. I'd got safe spot 650W Seasonic and call it a day.  Also, the specs for the processor would be more like the 3950x is and the 3070Ti would definitely gobble 250W so 550W PSU might be a little short. Someone mentioned, the CPU and GPU will not be utilized by 100% (or close) at the same time. Well that depends. If you are planning on a live stream or do some work involving CPU and GPU working together at near max I wouldn't risk the 550Watt PSU no matter how expensive it is.
> The other question about your current PSU is, how old is it?


It's less than a year old, and it's been sitting idle in an empty case for a good month or two by now.


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## ratirt (Oct 13, 2020)

AusWolf said:


> It's less than a year old, and it's been sitting idle in an empty case for a good month or two by now.


You can use it if you want but for the build you're going for I personally would go for a stronger PSU.


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## John Naylor (Oct 13, 2020)

Another case or "Premature Postulation".   May I suggest waiting a bit ?....

a)   You are choosing componentry "let's make a deal" style .... Do you want this what is available now for which we know everything about it  or what's behind the curtain which we know nothing real about  for another week or so ?
b)  Wouldn't the decision be easier after you know what the wattage of these components are ?
c)  We advise all our users to  wait till the for the 2nd or 3rd steppings of all new PC componentry .... think of all these people who ...

- I bought an early stepping MoBo for Sandy Bridge and had to have my MoBo replaced with a 3rd stepping MoBo because of a bum chipset
- I bought a 6 pin RX 480 ... oops,
- I bought a MSI 970 on release day and when I removed the adhesive tape, I broke one of my fans
- I bought a EVGA 970 and can't OC it because 1/3 the heatsink missed the GPU
- I bought an EVGA 1060, 1070, 1080 SC or FTW and they shipped without thermal pads ... at least the pyrotechnics were fun to watch.
- I bought an Asus Maximis VI Formula MoBo w/o waiting for the C3 stepping (4 months after initial  release) and now all my external devices won't wke up when the PC comes out of sleep mode and I have to reboot.

The potential for Buyer's Remorse to my eyes outweighs the opportunity to be the 1st one on the block with the new thing.     I'd counsel, at the very least, waiting to see what's the real performance is ****in apps that you actually use**** ...   and what the real power consumption before making that decision.  Later steppings means most hardware and design faults hav e been corrected, BIOSs are stable, due to production line improvements your chances of doing better in the silicon lottery are higher and supply catches up with demand and the price gouging period is over.  And if you live in US ... we may be saying our final goodbye to  tariffs on PC *component* importswhere said components are not available from other countries.... and hopefully replaced by a tariff on the now  exempt full assembled.


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## AusWolf (Oct 14, 2020)

John Naylor said:


> Another case or "Premature Postulation".   May I suggest waiting a bit ?....
> 
> a)   You are choosing componentry "let's make a deal" style .... Do you want this what is available now for which we know everything about it  or what's behind the curtain which we know nothing real about  for another week or so ?
> b)  Wouldn't the decision be easier after you know what the wattage of these components are ?
> ...


All I can say is: fair enough. I never buy anything until I've read more than a couple reviews anyway.


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## Bones (Oct 14, 2020)

I'd have to say upsize it a little or by however much you want really. 

The one you have now should be able to run it but like another has said you're close to the edge. Also by upsizing the next build could probrably use it without worry, this way you'd not have to buy another one the next time or two you upgrade. I don't know how often you do but that's an eventuality, many do it every two to three years and a good PSU will last way longer than that.

Just make sure if you do replace, to get one with alot of cables available for different things to accomidate what you may have later without worrying if you have the right cable or enough of them for your planned build. Modular PSU's are good for this, just add what you want and leave out what you don't. 

Any good quality 750W PSU should hold you over for this and the next build too at least, plus you won't be right at the edge of what it needs to run. I've noted myself over time it seems setups are needing more and more power overall to run, the newest Nvidia card is an example of this and no telling what future cards will require regardless of who makes it. 

That's my take on it. 

Personally I've NO worries about that since I'm running a modular 1600W in this one, no way it's gonna have an issue about being too small for a very long time to come.


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## Zach_01 (Oct 14, 2020)

First,
I also suggest the OP to wait until people get their hands on them and post some reviews. Its 3 weeks...

Second,
My estimation...


xman2007 said:


> Both will likely be close to 300w gpu's, the 5950x whilst having a 105w tdp could well consume 180w+ at full tilt so you're nearly at 500w for just the cpu and gpu, whilst it's a damn fine 550w I really think you need 650-750w for this build.


If the OP is going for a 3070 or AMD equivalent, probably those GPU cards will be around 250W give or take.
The 5950X is a 105W TDP CPU, and if it is like the previous flagship (3950X, 105W TDP), and I dont doubt it wont, it will draw 142W (PPT) total package draw. Remember... Its an AMD, not Intel... 

A system like this when gaming for demanding graphics and nothing else I would say that it will draw around 400W average with short peaks to 450W.

For peak
GPU: ~260W max
CPU: ~90W max
Rest of system: ~100W max


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## kiriakost (Oct 14, 2020)

RTX 3000 series this has active power limiter circuitry, this makes it unable to drive consumption that high, that a PSU this will trigger it own protection. 
I am generous and I will offer 400W of my PSU total for the graphic card, and another 350W to anything else. 

Such a recommendation this is bulletproof , if you decide to discover CPU overclocking benefits as experiment. 
Because the PSU it will not limit you in any way, everything else this it will.


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## Vya Domus (Oct 14, 2020)

All the advice on here is a bit misleading.

That GPU is going to have a 250W TDP alone at the very least, the whole system can probably peak well over 400W, 550W seems too little to me. It's not a good idea to run a PSU close to it's maximum output, these things are designed with an optimal operating point in mind and if you're outside that failure rates increase by a lot even thought it's technically "fine".


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## kiriakost (Oct 14, 2020)

Vya Domus said:


> All the advice on here is a bit misleading.



Including your own.
Except if you deliver something more than ....*  the whole system can probably.. *


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## Vya Domus (Oct 14, 2020)

kiriakost said:


> Except if you deliver something more than ....*  the whole system can probably.. *



Can you ?


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## Jetster (Oct 14, 2020)

Maybe buy a new PSU when I build a new system.

Building a new system, use a new PSU, they don't last forever


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## Zach_01 (Oct 14, 2020)

Whoever has a similar system and done his homework upon hardware and his own system can easily estimate a very close to reality number(s).

After 50min of FarCry New Dawn
3 red boxes please:





Zach_01 said:


> First,
> I also suggest the OP to wait until people get their hands on them and post some reviews. Its 3 weeks...
> 
> Second,
> ...


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## pavle (Oct 14, 2020)

If your new configuration flows around 500W of power which is a good round estimate, an old rule used to be to have PSU 50% loaded for max. efficiency and least heat and noise, but you could come through with a good 750W PSU. Your Seasonic Platinum 550W would do but it would be nearly maxxed out. However since it's a quality and efficient PSU you can use it till it "gets tired" and only then change it to be most economical.


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## Chrispy_ (Oct 14, 2020)

The build looks fine for a 250W graphics card - The only suggestion I have to make is to buy DDR4-3600 as Zen3 uses the same IO die with the same memory controller as Zen2 and 3600 is the sweet spot.

Dominator is expensive RAM, and if you're going for premium RAM then you might as well get the best speed for Ryzen - 3600 isn't much more expensive and the extra 200MHz on the infinity fabric is worth more performance than fancy heatspreaders or tighter timings at the lower 3200MHz speed.

The CPU will peak at around 150W (if AMD are to be believed about the exact same power draw as Zen2) and we'll need to wait on reviews to see what the power consumption of either the 3070Ti or 6900XT are. If the 3070Ti is a cut down 3080 then you may be out of luck with your 550W. You should add your peak CPU and GPU power draw together - AS TESTED, not as claimed by TDP figures - and make sure that the PSU can handle that. As others have said it's extremely unlikely that you'll ever be able to pull peak power out of both at once, but running an older PSU beyond 100% of its rating is just asking for component failure in the PSU, even in a high-quality model like your Seasonic.


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## kiriakost (Oct 14, 2020)

Vya Domus said:


> Can you ?



This question makes me wonder if my profile information this appears only to me. 


			https://www.techpowerup.com/forums/members/kiriakost.63752/#about


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## Vya Domus (Oct 14, 2020)

kiriakost said:


> This question makes me wonder if my profile information this appears only to me.
> 
> 
> https://www.techpowerup.com/forums/members/kiriakost.63752/#about



Thought so.


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## Zach_01 (Oct 14, 2020)

Chrispy_ said:


> *The CPU will peak at around 150W (if AMD are to be believed about the exact same power draw as Zen2)* and we'll need to wait on reviews to see what the power consumption of either the 3070Ti or 6900XT are. If the 3070Ti is a cut down 3080 then you may be out of luck with your 550W. You should add your peak CPU and GPU power draw together - AS TESTED, not as claimed by TDP figures - and make sure that the PSU can handle that. As others have said it's extremely unlikely that you'll ever be able to pull peak power out of both at once, but running an older PSU beyond 100% of its rating is just asking for component failure in the PSU, even in a high-quality model like your Seasonic.


Thats a 142W if exactly the same as ZEN2. As I said the system will be around 400W avg and 450W peak with a 250W GPU. Its is within PSU specs but still its a 75~80% load.
I personally wouldnt run that for long... As a matter of fact... at all. Especially if that PSU has a few hundread (or more) hours on its back.


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## AusWolf (Oct 14, 2020)

Bones said:


> I'd have to say upsize it a little or by however much you want really.
> 
> The one you have now should be able to run it but like another has said you're close to the edge. Also by upsizing the next build could probrably use it without worry, this way you'd not have to buy another one the next time or two you upgrade. I don't know how often you do but that's an eventuality, many do it every two to three years and a good PSU will last way longer than that.
> 
> ...


To be honest, my way of thinking has changed a lot recently from _"mid-tier will always be fine for 1080p gaming"_ all the way to _"I want the best I can afford to make sure I won't have to upgrade so often"_. But even if I don't upgrade for a good 3-4 years, future compatibility will always be a thing, and the PSU isn't something you'd want to think about just for an upgrade - you'd want it to serve you as long as its lifespan allows.

Now that I've read a bunch of opinions and suggestions, I think I have a plan:
1. I'll wait for reviews (as I intended anyway), and see if _actual_ power consumption figures necessitate a PSU swap.
2. I'll try using the current PSU if I can, and save up for a replacement whether it works or not.

Speaking of replacement, what do you guys recommend? I love my Prime Ultra Platinum, but it's a bit on the expensive side in the 750 W version. Would I be alright with a Focus GX? As far as I can tell, the only difference between that, and the Prime line is the fan size, which is a bit confusing.


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## Zach_01 (Oct 14, 2020)

AusWolf said:


> Speaking of replacement, what do you guys recommend? I love my Prime Ultra Platinum, but it's a bit on the expensive side in the 750 W version. Would I be alright with a Focus GX? As far as I can tell, the only difference between that, and the Prime line is the fan size, which is a bit confusing.



I cannot recomend you a PSU (Brand) as others know better, but I'm certain that you dont need a platinum one. A Gold and 750W will be plenty.


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## AusWolf (Oct 14, 2020)

Zach_01 said:


> I cannot recomend you a PSU (Brand) as others know better, but I'm certain that you dont need a platinum one. A Gold and 750W will be plenty.


I've looked at the Prime GX 750 W as well, which is a good £50 more expensive than the Focus GX equivalent. Sure, it's got a bigger fan, but I really don't know if it's worth that much of an extra.

Edit: Or maybe an EVGA Supernova 750 GT? All of these are 80+ Gold models.


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## Chrispy_ (Oct 14, 2020)

Zach_01 said:


> Thats a 142W if exactly the same as ZEN2. As I said the system will be around 400W avg and 450W peak with a 250W GPU. Its is within PSU specs but still its a 75~80% load.
> I personally wouldnt run that for long... As a matter of fact... at all. Especially if that PSU has a few hundread (or more) hours on its back.


Yes and no. I'd round it up to 150W for safety but I really am spitballing numbers here without experience of the B550M TUF mentioned. 150W is a ballpark figure for a typical board on "auto" settings.

142W is the *MINIMUM* package power, along with 90A TDC and 140A EDC limits for a 105W-rated chip, as per AMD's specs for boosting. Most motherboards provide more headroom than this for PBO and many motherboards (Asus are one of the main offenders) apply aggressive (or lazy, depends how you look at it) voltages using "auto" settings even when PBO isn't enabled - all of which serves to increase the peak power draw. On MSI B450 boards I actually had to tweak quite a lot of settings to get 3900X chips running at "stock" and not overclocked in any way.

The only real way to know is to find a review of that exact board that includes the same class of chip and has compreshensive power consumption figures, then deduct the (hopefully known) Idle GPU power draw to get your answer. Failing that, get a kill-a-watt meter and test yourself once you have the hardware in hand.

Normally I wouldn't care too much about +/-25W because most builds have plenty of headroom in the PSU, so it's the difference between the PSU operating at 60% load or 65% load there but given that the OP wants to run a potentially 300W+ graphics card with a PSU that's 200W less than the recommended Wattage, I guess every little bit matters. Certainly a 3900X with a RTX3080 would fail to boot on his 550W PSU - quite a few mainstream reviewers commented on having to upgrade their test-bench PSU in order to get their 3080 and 3090 reviews done because of the insane peak draw of those cards.


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## Rei (Oct 14, 2020)

Spare your expenses if you are sticking with your currently planned build. Your current PSU is still good for your upcoming rig. Best to upgrade the PSU on your next upgrade cycle when changing to a more power-hungry component and have lots of USB and other peripherals plugged in. No need to blow over the budget for something that is not yet necessary.


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## Zach_01 (Oct 14, 2020)

Chrispy_ said:


> Yes and no. I'd round it up to 150W for safety but I really am spitballing numbers here without experience of the B550M TUF mentioned. 150W is a ballpark figure for a typical board on "auto" settings.
> 
> 142W is the *MINIMUM* package power, along with 90A TDC and 140A EDC limits for a 105W-rated chip, as per AMD's specs for boosting. Most motherboards provide more headroom than this for PBO and many motherboards (Asus are one of the main offenders) apply aggressive (or lazy, depends how you look at it) voltages using "auto" settings even when PBO isn't enabled - all of which serves to increase the peak power draw. On MSI B450 boards I actually had to tweak quite a lot of settings to get 3900X chips running at "stock" and not overclocked in any way.


142W is the limit for the 105W TDP CPUs, and you cant see a figure past, even with PBO on and CPU power management settings on Auto, unless you cool the CPU really low (like <60C). But I completely forgot the "PowerReportDeviation" issue. The subject that almost every board lies about its power draw to the CPU itself. So, yes partially you are right. It could reach 150W true power.


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## Bones (Oct 14, 2020)

Alot of different takes on how to go about it here and TBH none are really "Wrong" so much but it's the fact your setup is/will be close to the edge that bothers me with the current PSU, esp since it has a bit of age on it.

All I'm wanting to do is suggest something that will work, not be too expensive, have a minimum of worry with it too so you'll at least be able to use the system once built up until the time to upgrade comes around again.

I normally spec things to about 80% of it's power rating as a nominal figure with all the expected wattage load and go from there to accomidate for any load spikes the system may and will have at times. This way it doesn't make the PSU itself run under what would be a heavily loaded condition all the time - That will place unneccesary strain on the PSU and tend to shorten it's life.

The big thing here to me is to be sure once the system is built you won't run into problems with it and also to help avoid a sudden PSU failure which can and normally will take out the rest when it goes.

It may not happen for sometime to come but once it does it's already too late and expensive to deal with, certainly costing more than the extra spent on one that's little higher in wattage rating. I'm also aware they can even go out to the point of flaming death and that's never a good thing for it and your own safety.

Just ask @Mr.Scott about that sometime - He'll tell you what happened with one of his when it did just that.

Your call.


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## AusWolf (Oct 14, 2020)

Bones said:


> Alot of different takes on how to go about it here and TBH none are really "Wrong" so much but it's the fact your setup is/will be close to the edge that bothers me with the current PSU, esp since it has a bit of age on it.
> 
> All I'm wanting to do is suggest something that will work, not be too expensive, have a minimum of worry with it too so you'll at least be able to use the system once built up until the time to upgrade comes around again.
> 
> ...


It sounds a little bit extreme, but of course everything's possible. I'll try to squeeze a new PSU into the budget, or wait with buying the graphics card until I have the money for both the GPU and PSU... or go with the original plan: try my luck with the current one, and start saving for a new one anyhow. We'll see.



Chrispy_ said:


> Dominator is expensive RAM, and if you're going for premium RAM then you might as well get the best speed for Ryzen - 3600 isn't much more expensive and the extra 200MHz on the infinity fabric is worth more performance than fancy heatspreaders or tighter timings at the lower 3200MHz speed.


I've just spent a little bit of time looking into this. As far as I see, 3200 MHz is more widely available in my area, and is also fairly cheaper (depending on the model of course). On the other hand, the difference in performance appears to be marginal. It seems to me like the "nvme vs SATA" situation: even though one is faster than the other _on paper_, you have to focus hard to spot any real world difference. Although, I've never owned a Ryzen 3000 system, so feel free to correct me if I'm wrong.


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## Bones (Oct 14, 2020)

Doesn't have to be anything way over the expected wattage useage, just something you know will handle it if anything will.
Even a good quality 650W is better than what you've got ATM so you're not constantly bumping the ceiling with what it can handle.

Just add up the expected total wattage (Nominal) useage and figure what 10% of that would be, then simply double it to get the 20% cushion value you'd want.

Add this 20% to the original expected useage (Nominal) value and that will give an approximate wattage to get in a PSU and that's all you'd need to worry about.


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## AusWolf (Oct 14, 2020)

Bones said:


> Doesn't have to be anything way over the expected wattage useage, just something you know will handle it if anything will.
> Even a good quality 650W is better than what you've got ATM so you're not constantly bumping the ceiling with what it can handle.
> 
> Just add up the expected total wattage (Nominal) useage and figure what 10% of that would be, then simply double it to get the 20% cushion value you'd want.
> ...


Interesting recipe.  What I'd do is: CPU TDP + GPU TDP + 100 W (for the rest of the system and a little headroom). Based on pre-launch estimates, this gives me 505 Watts, so my Seasonic may or may not be OK... hence my OP. With your method it's 105 W + 300 W + 20% = 486 W. Again, it's close to the ceiling, which may end up OK, or may not.


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## Bones (Oct 14, 2020)

AusWolf said:


> Interesting recipe.  What I'd do is: CPU TDP + GPU TDP + 100 W (for the rest of the system and a little headroom). Based on pre-launch estimates, this gives me 505 Watts, so my Seasonic may or may not be OK... hence my OP. With your method it's 105 W + 300 W + 20% = 486 W. Again, it's close to the ceiling, which may end up OK, or may not.



That's correct but also take into account the age of the PSU, that does matter to an extent. 

You can exceed that value if you want to accomidate the age of the current unit. I know any PSU technically can handle spikes of 100%+ of it's value but that will change with age of course as you'd expect.
With that even a 600W unit would be the ticket here as long as it has all the connectors you need.


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## Chrispy_ (Oct 14, 2020)

AusWolf said:


> Interesting recipe.  What I'd do is: CPU TDP + GPU TDP + 100 W (for the rest of the system and a little headroom). Based on pre-launch estimates, this gives me 505 Watts, so my Seasonic may or may not be OK... hence my OP. With your method it's 105 W + 300 W + 20% = 486 W. Again, it's close to the ceiling, which may end up OK, or may not.


I'm curious where you're getting TDP figures for the unannounced 3070Ti and remember that the TDP figures for the 3000-series are not accurate to their real-world power draw.



AusWolf said:


> I've just spent a little bit of time looking into this. As far as I see, 3200 MHz is more widely available in my area, and is also fairly cheaper (depending on the model of course). On the other hand, the difference in performance appears to be marginal. It seems to me like the "nvme vs SATA" situation: even though one is faster than the other _on paper_, you have to focus hard to spot any real world difference. Although, I've never owned a Ryzen 3000 system, so feel free to correct me if I'm wrong.


For Zen2 the gaming performance increase moving from 3200 C16 to 3600 C16 is about 4-5%, same for encoding. It doesn't make much difference to rendering though.

Take the total cost of your system upgrade, (probably ~$1000) add 4-5% (so $40-50) and if the DDR4-3600 is less than a $40-50 premium then it is both faster and better value for money.

Don't get me wrong, 3200MHz RAM is fine but you're leaving some performance on the table by not picking it. Even if you have to drop down to a cheaper kit with looser timings, it's worth doing. Expensive 3200 CL14 is still inferior for Zen2 (and presumably Zen3) than a cheapo 3600 CL17 kit because It's not about RAM bandwidth or RAM latency, it's about running your CPU's infinity fabric* at its maximum clock, which is still  going to be of huge importance on Zen3 if you're using a CPU with two chiplets (so the 12-core and 16-core variants). Zen 3's change to CCX cache means that 8-core and 6-core models won't be as sensitve to RAM speeds for Zen3 as they are with Zen2.

* - Edit: In case you aren't aware, your CPU's infinity fabric is locked to the RAM speed. You can't run the Infinity fabric at it's maximum (official) 1800MHz whilst using DDR4-3200 that only runs at 1600MHz. The 1600MHz RAM clock will drag your CPU's internal fabric clock (FCLK) down by 12% and whilst this is only a minor performance hit, it's still a performance hit.


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## AusWolf (Oct 14, 2020)

Chrispy_ said:


> I'm curious where you're getting TDP figures for the unannounced 3070Ti


I used the preliminary data on the RX 6900 XT page of TPU's GPU database. Needless to say that everything is speculation as of now.


Chrispy_ said:


> remember that the TDP figures for the 3000-series are not accurate to their real-world power draw.


True. I might be better off postponing on the graphics card a couple months, and buying it together with a bigger PSU. I will also have more (real world) data to go by at that point.


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## Bones (Oct 14, 2020)

Chrispy_ said:


> I'm curious where you're getting TDP figures for the unannounced 3070Ti and remember that the TDP figures for the 3000-series are not accurate to their real-world power draw.



Have to agree - You have to know all that before doing a final figuring of the expected wattage draw to get it right. Was going on the values the OP provided but if that's not accurate then perhaps a minimum 100W cushion would do based on the proposed build.
Whatever it winds up being is what to base it all on.


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## AusWolf (Oct 14, 2020)

Chrispy_ said:


> I'm curious where you're getting TDP figures for the unannounced 3070Ti and remember that the TDP figures for the 3000-series are not accurate to their real-world power draw.
> 
> 
> For Zen2 the gaming performance increase moving from 3200 C16 to 3600 C16 is about 4-5%, same for encoding. It doesn't make much difference to rendering though.
> ...


Fair enough. I thought 3200 MHz was the fastest officially supported speed (and thus 1600 MHz fclk), anything above was overclock.


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## Chrispy_ (Oct 14, 2020)

AusWolf said:


> Fair enough. I thought 3200 MHz was the fastest officially supported speed (and thus 1600 MHz fclk), anything above was overclock.



That, I think, is because the fastest _official_ JEDEC standard for DDR4 is 3200, there is no such thing as JEDEC 3600. Technically, every DDR4-3200 kit is also an overclock because the XMP timings will be CL16 or similar - the official JEDEC timings are a ridiculously-loose CL22 or even CL24 I think....

At Zen2 launch, AMD put on several presentations about the architecture and went into detail about the fabric speeds and RAM divider. The 1:1 divider between RAM and FCLK automatically drops to 1:2 at DDR4-3733, so AMD officially caps its own FCLK at 1833MHz and are on record recommending 3600MHz DDR4 and 1800MHz FCLK as the sweet spot for Zen2 performance.

It turns out that if you bought a bargain-basement 3600 or 3100 that's low-yield in the silicon lottery, you may find that 1800FCLK isn't actually possible and you have to drop down to 1766MHz - but that's also usually a factor of cheap motherboard and cheap power supply all playing their part too. Realistically, the Zen2 I/O die will handle 1800MHz+ as long as you don't buy low-end parts and that's why AMD set the FCLK:RAM divider to cap FCLK at 1800MHz. You can override this AMD-official divider with many motherboards to push your FLCK beyond 1800MHz, but up to 1800 FCLK is 100% 'stock' as far as AMD are concerned.


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## AusWolf (Oct 14, 2020)

Chrispy_ said:


> That, I think, is because the fastest _official_ JEDEC standard for DDR4 is 3200, there is no such thing as JEDEC 3600. Technically, every DDR4-3200 kit is also an overclock because the XMP timings will be CL16 or similar - the official JEDEC timings are a ridiculously-loose CL22 or even CL24 I think....
> 
> At Zen2 launch, AMD put on several presentations about the architecture and went into detail about the fabric speeds and RAM divider.
> 
> ...


It makes a lot more sense now. So basically, 3200 MHz RAM / 1600 fclk is the fastest officially supported and guaranteed speed on all Zen 2 CPUs, even though 3600/1800 MHz technically works with most chips, right? Then I guess they class 3600 MHz memory as overclock just to avoid a potential lawsuit coming from 0.1% of the users who couldn't make it work with their 3100X CPUs (again, correct me if I'm wrong).


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## xtreemchaos (Oct 14, 2020)

i allways like to have a high wattage PSU i run a 850w its loads morethan i need near double but its better to have it and not need it than to need it and not have it same rules as a condom   . + ive a hybred and the fan only comes on when im pulling 500w or more is which almost never.


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## tabascosauz (Oct 14, 2020)

AusWolf said:


> It makes a lot more sense now. So basically, 3200 MHz RAM / 1600 fclk is the fastest officially supported and guaranteed speed on all Zen 2 CPUs, even though 3600/1800 MHz technically works with most chips, right? Then I guess they class 3600 MHz memory as overclock just to avoid a potential lawsuit coming from 0.1% of the users who couldn't make it work with their 3100X CPUs (again, correct me if I'm wrong).



Yeah, that's just about the number of people having trouble sustaining 1800MHz FCLK. At launch (when quad-core Zen 2 didn't exist), there were some early production 3600 chips that had trouble running 1800; I would imagine that with the new positioning, the 3100 is the only SKU that's possibly more vulnerable than the rest.

I would probably make a distinction between the on-I/O die memory controller and the on-substrate Infinity Fabric. Whatever Infinity Fabric connections exist on the chiplets themselves aren't the issue, and neither is the memory controller (which is plenty capable of 4000MT/s on its own, even in lower SKUs); the problem exists with trying to get the routing located on the _substrate _itself up to speeds beyond 1800/1833/1866/1900/1933MHz.

The other issue there is that when an average users encounters "difficulty running a 3600MT/s kit", there exists a billion other places from which the instability can stem. Which memory ICs they use and the timings settled on by the board outside of the few XMP-dictated ones, the binning of the ICs within that die revision type alone, appropriate DRAM voltage, appropriate SOC voltage for the speed, stock procODT settings dictated by the board, etc. So you'd be able to verify whether an inability to run FCLK 1800MHz is actually just that, only after hours or days of testing that your average Joe would never undertake. You'll never know if those users really had a CPU incapable of running FCLK 1800, or if there were other issues at play.

If you're looking towards an 8-core or dual-chiplet CPU, I don't see there being a single issue with setting your sights on a decent 3600CL16 kit. Even with 3200MT/s XMP kits, full stable compatibility is hardly guaranteed (just take a look around the web at all the troubleshooting threads); there are countless things that can come in the way of RAM stability, none of which are 1:1 FCLK speed concerns.

The *only *higher speed kits that I would consider to be largely fail-safe from everything would be less common 3200MT/s kits that run at CL22 timings at strictly the baseline DDR4 1.2V. These generally don't rely on XMP profiles to hit those speeds out of the box, and are IFAK covered by JEDEC 3200. As you can probably tell, you probably don't want these for their performance.


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## rbgc (Oct 14, 2020)

Recomended PSU Table for GPU a CPU (Source: ASUS, Manuals, PSU)


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## 300BaudBob (Oct 15, 2020)

For anyone interested in why keeping a power supply for many years is not really a great idea this PDF from NASA is worth a read.


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## Selaya (Oct 16, 2020)

The system is very unlikely to load _both_ the CPU and GPU to the max at the same time - games that are CPU (multithread) bound/bottlenecked, if they do exist and max the CPU will in all likeliness drop the GPUs power, and vice versa.
I would assume that both the 3070 and the 5950X's power consumption will be within the ballpark of the 2080Ti and 3900X/3950X's, and W1zzard was kind enough to do total power consumption tests for the latter - the system will max out at about 400W draw at the wall.
While you may want to consider ordering a higher-specced PSU (if you don't already have one), the 550W-rated one will do just fine - it's certainly not worth spending another $200+ on a new PSU just for like, a 10% efficiency upgrade at 400W - you'd have to run your system at close to maximum power drawn for several years straight for your PSU investment to amortise.

Also, a 550W PSU is probaly safe enough to operate even for at 600-650W for a short timeframe in the unlikely event that your system really maxes out both the CPU _and_ the GPU's power draw for whatever reason.


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## AusWolf (Oct 17, 2020)

Selaya said:


> The system is very unlikely to load _both_ the CPU and GPU to the max at the same time - games that are CPU (multithread) bound/bottlenecked, if they do exist and max the CPU will in all likeliness drop the GPUs power, and vice versa.
> I would assume that both the 3070 and the 5950X's power consumption will be within the ballpark of the 2080Ti and 3900X/3950X's, and W1zzard was kind enough to do total power consumption tests for the latter - the system will max out at about 400W draw at the wall.
> While you may want to consider ordering a higher-specced PSU (if you don't already have one), the 550W-rated one will do just fine - it's certainly not worth spending another $200+ on a new PSU just for like, a 10% efficiency upgrade at 400W - you'd have to run your system at close to maximum power drawn for several years straight for your PSU investment to amortise.
> 
> Also, a 550W PSU is probaly safe enough to operate even for at 600-650W for a short timeframe in the unlikely event that your system really maxes out both the CPU _and_ the GPU's power draw for whatever reason.


Thanks for the confirmation, I hope you're right.  Thanks to the rest of you as well for the valuable input.

I think I've decided what I'm going to do. Presumably, the new Ryzen CPUs come out way before the RX 6900 XT (not to mention the unannounced 3070 Ti/Super), so I will buy the mobo, CPU, cooler and RAM first anyway. My 550 W Seasonic will be more than adequate to run all of this with my GT 1030 while I'm waiting for the new GPU. This will also give me plenty of time to test total system power consumption with the GT 1030 in it, so later I will have an idea of were I need to be in terms of PSU based on reviews of the new GPUs. If I'm fine, I'm fine. If not, I'll buy a new PSU together with the GPU.


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