# How much phases I need on motherboard to match for cpu



## khjhpopasa (Dec 9, 2020)

How much phases I need on motherboard to match for cpu and even cpu for OC

for example if I buy R7 5800X motherboard with 8 phases be enough  or need more? 
if yes can do OC? or need 8 for basic without OC and 10 for nice OC
how can I calculate it?
thanks for helping guys!!


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## jayseearr (Dec 9, 2020)

sounds like your trying to overcomplicate something for no reason. Why break down a bunch of complicated math equations when you can just go look at reviews? Generally speaking (not always) if a motherboard is made to work with "X" cpu then the VRMS are more than capable of handling it. Every once in a while you get some stinker boards (the msi x570 carbon and gaming edge come to mind) with inadequate VRM's but they are few and far between. simply look at a review with X board and Y cpu to get a general baseline of what you can expect. If a certain board is garbage and has bad vrm's it wont be too hard to figure that out with a little digging on the internet.


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## EarthDog (Dec 9, 2020)

How _many_ phases? Thats a complicated question as its more than just phase count that matters...

Which is better 4 phases with 90A MOSFET, or 6 with 60A MOSFET? What about 12 phases but doubled versus 6 real?

Let's move past the count and simplify things... what is your budget for the motherboard? What cpu is going in it? And i assume you plan to overclock, right?



jayseearr said:


> Why break down a bunch of complicated math equations


It isn't math equations (current capability is # of phases x MOSFET amperage)? There are more details than that, but to figure out current capability doesn't require past elementary school math. Understanding and applying some of the actual details of why one config is better than the other, however, does require a bit of knowledge. 

I can show you a handful of cheap arse mobos that claim 5950x support but can't or can barely handle the CPU at stock speeds. So that is, as you said, generally correct, but there are enough examples at the cheap end of the spectrum where just a list of supported CPUs isn't telling the whole story.


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## NoJuan999 (Dec 9, 2020)

What Motherboards are you considering ?
Pretty much any decent B550 or X570 will have no problem running a 5800x (OC'd via PBO or All Core).
I have an Asus ROG Strix X470-F (6+2 Phase) and I am very confident that it would have No problem running a 5800x.


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## kapone32 (Dec 9, 2020)

NoJuan999 said:


> What Motherboards are you considering ?
> Pretty much any decent B550 or X570 will have no problem running a 5800x (OC'd via PBO or All Core).
> I have an Asus ROG Strix X470-F (6+2 Phase) and I am very confident that it would have No problem running a 5800x.


That is much more relevant question.


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## jayseearr (Dec 9, 2020)

EarthDog said:


> How _many_ phases? Thats a complicated question as its more than just phase count that matters...
> 
> Which is better 4 phases with 90A MOSFET, or 6 with 60A MOSFET? What about 12 phases but doubled versus 6 real?
> 
> ...


Fair enough, i see what you're saying and i mostly agree. My underlying point was don't attempt to use math to decide which board is right for which cpu regardless of how simple or complicated it may seem. There is no math equation that is going to to tell you whether or not a board is notoriously bad with bios issues, there is no math equation that will tell you if a board is notoriously bad with memory compatibility etc etc. The way to pick a board is by doing research and looking at credible reviews. That should tell you everything you need to know (including VRM capabilities)


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## EarthDog (Dec 9, 2020)

jayseearr said:


> My underlying point was don't attempt to use math to decide which board is right for which cpu regardless of how simple or complicated it may seem.


But it's math that can tell you what has the better VRM. Phase count doesn't do it, but phase count + knowing the rating of MOSFET gives you a better (not best) idea.

You're right about the rest, that math doesn't tell you those things, however, the OP isn't looking for the other (random) stuff you just brought up. I'm solely talking under the context of the thread/OP... VRMs. 


jayseearr said:


> The way to pick a board is by doing research and looking at credible reviews.


This!


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## jayseearr (Dec 9, 2020)

EarthDog said:


> But it's math that can tell you what has the better VRM. Phase count doesn't do it, but phase count + knowing the rating of MOSFET gives you a better (not best) idea.
> 
> You're right about the rest, that math doesn't tell you those things, however, the OP isn't looking for the other, random, stuff you just brought up. I'm solely talking under the context of the thread/OP... VRMs.


Yes, true but that also threads into my other point (about overcomplicating) over-complicating simple choices is a very real thing. If you are looking for a in-depth fundamental understanding of how power delivery works on motherboards, and how it pertains to cpus more power to you (no pun intended) but there are school courses dedicated to this kind of stuff...you could dedicate your entire life towards research on power delivery and probably even make a career out of it somehow if you really wanted, but if you're just a casual consumer trying to figure out which board to buy it's more than likely a waste of time. Most people don't worry about the science and chemistry of air compressors when they go to buy a fridge right? You don't need to be a software engineer in order to use windows, right?


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## EarthDog (Dec 9, 2020)

jayseearr said:


> Yes, true but that also threads into my other point (about overcomplicating) over-complicating simple choices is a very real thing. If you are looking for a in-depth fundamental understanding of how power delivery works on motherboards, and how it pertains to cpus more power to you (no pun intended) but there are school courses dedicated to this kind of stuff...you could dedicate your entire life towards research on power delivery and probably even make a career out of it somehow if you really wanted, but if you're just a casual consumer trying to figure out which board to buy it's more than likely a waste of time. Most people don't worry about the science and chemistry of air compressors when they go to buy a fridge right? You don't need to be a software engineer in order to use windows, right?


In the end, all I was saying is that simple math can give you a general idea of the VRM capability...better than phase count alone which isn't a great barometer. At a high level, more is better... but again, 10 phases at 50A or 6 at 90...which can handle more current? Math answers that high level quandry. Nobody is talking EE level knowledge here. But as a consumer, you need to know some details on your fridge, right? Not that there are three doors, shelves and a freeze. Here, if you're asking about phase count in reference to overclocking, a little supplemental information about the metric doesn't hurt. It isn't complicated math to figure that high-level bit of information out.

...along with....

...as you said, simply checking reviews of the motherboard. 

You don't need to look for a specific CPU, any quality review (worth a salt) uses flagships on 90% of reviews or, at minimum, mentions VRMs and it's capability...they should give you a good idea of its overclocking capabilities. TPU/Tom's/Anandtech/Overclockers.com/Guru3D/GN/Tweaktown etc... all pretty solid.

Anyway, sorry for splitting hairs here.


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## Hattu (Dec 9, 2020)

I think i saw a link to a spreadsheet somewhere on these forums, that listed many AMD motherboards and their vrms suitability to different cpus. Anyone?


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## Athlonite (Dec 9, 2020)

I wouldn't go below a high midrange B550/X570 mobo for a R7 5800X or better and it's not just about phases and current rating of mosfets it's also about the quality of the components as not all mosfets are created equal so without having to get into all the nitty gritty just buy a high mid range mobo and you should be good to go


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## NoJuan999 (Dec 9, 2020)

Hattu said:


> I think i saw a link to a spreadsheet somewhere on these forums, that listed many AMD motherboards and their vrms suitability to different cpus. Anyone?


Here are a few:
AM4 Vcore VRM Ratings v1.4 (2019-11-07) - Google Drive 
X570/X470/X370/B550/B450/B350/A520/A320 Motherboards (AM4-socket for AMD Ryzen CPUs) Comparison - Google Drive 
Motherboard VRM Tier List v2 (currently AMD only) - CPUs, Motherboards, and Memory - Linus Tech Tips
What's under the heatsink? Things they don't mention -come on Intel, make me interested - Google Sheets


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## khjhpopasa (Dec 10, 2020)

NoJuan999 said:


> Here are a few:
> AM4 Vcore VRM Ratings v1.4 (2019-11-07) - Google Drive
> X570/X470/X370/B550/B450/B350/A520/A320 Motherboards (AM4-socket for AMD Ryzen CPUs) Comparison - Google Drive
> Motherboard VRM Tier List v2 (currently AMD only) - CPUs, Motherboards, and Memory - Linus Tech Tips
> What's under the heatsink? Things they don't mention -come on Intel, make me interested - Google Sheets


cool Thanks


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