PSU for multiple graphics cards

Noemis95 · May 30, 2015

Hi,
I was wondering whether my psu would provide enough power for this build: http://pcpartpicker.com/p/FkbdP6 as it contains two gtx 970 graphics cards.
pcpartpicker sais it does and the xfs xtr site (http://xfxforce.com/en-us/products/xtr-series-full-modular/xtr-series-650w-psu-p1-650b-befx) says my psu supports up to 2 gpu's, but I've heard that 650W might not suffice, so I'm a little uncertain.
Thanks!

tiny voices · May 30, 2015

technically it will work, but a 750w unit would be more ideal.

Sammyjo20 · May 30, 2015

Should be fine mate. Just make sure you have enough PCI-E power connectors.

Both GPU's and your CPU will only use about 378 watts.

- Sam

tiny voices · May 30, 2015

^not true.

http://www.tomshardware.com/reviews/nvidia-geforce-gtx-980-970-maxwell,3941-13.html

In gaming a 970 can pull 179w multiply by 2 = 358w for JUST the GPUs. A 4790k STOCK can pull 100w and overclocked can get close to 140w. That's 458w for just the CPU (not overclocked) and GPUs under full load. Plus about 50w for the rest for the rest of the system (overestimate on purpose).

Under normal gaming load nothing will remain locked at 100% all the time so expect like 450w power consumption form the system not overclocked in a AAA game.

So 650w is safe, but as you saw in the benchmark for the GPUs, if you plan to do any stress testing/benchmarking software, a single 970 would pull 243w and if have 2 of those and an overclocked CPU, you will easily hit 650w, and that is OK for a quality PSU to do like yours, but I would NOT recommend you do it often or even at all.

So, in short, for general gaming use, 650w is plenty, but there ARE circumstances with the same system where it could be barely enough or not even enough at all.

750w would really be ideal, then no matter what, you cannot over draw it.

johnnyb105 · May 30, 2015

FOR THE cost of the power supply 109 bucks I think you can find a better buy with more wattage for that price...

Sammyjo20 · May 30, 2015

Sorry. I'm just reading what sites say but If it were me, I would get a 750 watt. I was saying like you said, it'll work. I'm not recommending it.

- Sam

Noemis95 · May 30, 2015

Thank you very much for your quick answers! I'll leave it as it is then, as 650W is expensive enough already

tiny voices · May 30, 2015

Buy you can get a similar quality 750w unit for the same or less money....

tiny voices · May 30, 2015

http://pcpartpicker.com/part/evga-power-supply-110b20750vr

VERY good quality unit.

Sammyjo20 · May 30, 2015

Noemis95 :

Yeah mate, Listen to Tiny Voices. You can get a 750 for the same price.

- Sam

tiny voices · May 30, 2015

^ or less.

Noemis95 · May 30, 2015

Sorry, I only just read your discussion, I'll go for a 750W one then. Thank you all very much for your help!

Sammyjo20 · May 30, 2015

Noemis95 :

No probs. Have a good day

- Sam

tiny voices · May 30, 2015

Post the 750w unit you plan to buy so we can ensure it is good. For every quality PSU on the market, there are 10 junk ones.

Sammyjo20 · May 30, 2015

^ Very true. Before I knew as much as I know now about PC's, I was going to get an 800 watt PSU from "Novatech" for £30!! Then I realised it wasn't efficient at all and my friend had it and it popped on him in 2 days destroying his whole system and nuking his very expensive RAM.

- Sam

tiny voices · May 30, 2015

Yeah, there are way too many people running around recommending poor quality PSUs thinking they are very good because of a brand name.

The Corsair CX units are the biggest example of this. People assume quality because they see "Corsair" on the sticker. In reality Corsair make quite a few poor quality units.

Noemis95 · May 30, 2015

tiny voices :

I'm not an expert tiny voices, so I guess I'll just take the EVGA http://pcpartpicker.com/part/evga-power-supply-110b2075... you recommended. If I do change my mind, I'll post an answer here. Thanks again and have a good day

tiny voices · May 30, 2015

That is a VERY good PSU and will be excellent for your system.

Glad to help!

PSU for multiple graphics cards

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