I have been trying to figure out what kind of watt range PSU should I aim for my X370 pro gaming motherboard.

I ran into a weird range of watt usage on different calculators.

My setup is this:

AMD Ryzan 1700x at default speed (no OC)
4x 16 DDR4
Dual Radeon RX 570 and SLI/CF (no OC)
2x M.2 SSD
2x SSD
2x monitor LCD 20 inch

Now Outervision says go for about 491 Watt or so. Which seems very low considering all things!

While Newegg doesn't seem to have put in RX 570 value in yet porperly so I replaced with RX 480 and it comes out at 696 Watt.

Evga power meter says 600 watt which undercut Newegg's estimate.

I am going to not setup all of this right away now and I may eventually upgrade to this later. For example at first I will only have one RX 570 GPU, fewer SSD more mechnical drives, and less RAM until I can afford to upgrade those.

So with all that in mind what kind of watt range should I aim for?

  • This question is leaning tech support, as you are not asking for a power supply, rather what wattage you need. This is easily fixed by changing the wording around a bit and adding a few requirements (price, energy efficiency, modular, included fan, etc).
    – Cfinley
    Commented Aug 2, 2017 at 2:24
  • According to this, a RX 570 uses around 225W at 100%, so two cards would be ~500W. Mechanical drives use up more energy than SSDs. Based on everything, I would be looking for at least 800W, but thats just me. I tend to not skimp out on the PSU.
    – Cfinley
    Commented Aug 2, 2017 at 2:31

1 Answer 1


Motherboard, ssd, and ram are all negligible wattage. I usually group them and say they use 100 watts max as computer parts are very efficient these days. But for the sake of calculating.

  • The RX 570 has a 120W TDP.
  • DDR4 is around 15W for four modules.
  • SSD is around 12W max for two.
  • NVME is around 14W max for two.
  • 1700x has a 95W TDP.
  • Motherboards (lga 775 gaming) use 40 to 75 watts This number is probably drastically lowered as modern motherboards are more efficient and consume less power.

Therefore you only need 451 W under max load. So you really only need a 550W powersupply. You could also get away with a 500W quality PSU as it's most likely your system won't be at 100% full GPU, CPU, SSD at any given point.

I should note that, you should probably look at getting the rx580 or rx480 instead of trying to crossfire weaker cards. Vega is also around the corner if you can wait. Crossfire has a slew of problems, and spotty game support. It's better to get a single powerful card.

  • The main reason I am looking at RX 570 now is that most RX 480/580 are out of stock on some web store. Especially Newegg. However you made a valid point about waiting for Vega. Sound like I am planning to wait on GPU for now.
    – Vyndicu
    Commented Aug 1, 2017 at 20:07
  • You sure about that TDP for the RX 570? AMD's website says "150W typical", while looking at actual cards gives numbers from 150W to 225W.
    – Mark
    Commented Aug 1, 2017 at 21:02
  • On newegg it states "Power Consumption: 120W" for third party rx570s. Looking at the powerdraw from my rx480 from msiafterburner I see 91W to 140W power draw. AMD maybe giving more headroom on their website.
    – Kaito
    Commented Aug 1, 2017 at 21:15

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