PSU for 970GTX SLI

Digitalle · 26 Sep 2014 at 15:10

I'm about to buy 2no. MSI 970's for SLI.

I currently have a Seasonic SS-550RM 550W Gold powering my HD 7970ghz.

Suggestions on the PSU I'm going to need?

Thanks

krooton · 26 Sep 2014 at 15:12

A decent 700w will do you fine with some headroom.

CinderzFTW · 26 Sep 2014 at 19:06

krooton said:
A decent 700w will do you fine with some headroom.

+1

Legojon · 26 Sep 2014 at 19:10

I'll know tomorrow if it is the psu or not, but my computer is currently in bits because my thermaltake toughpower 700w kept shutting down whilst playing games. It never did it with my 660 Tis, only with the 970 SLI. Going to OCUK tomorrow to pick up a new PSU! Will let you know if that was the cause.

CinderzFTW · 26 Sep 2014 at 19:27

pick up a good 850 or better to give you plenty of headroom

kefan77 · 26 Sep 2014 at 19:28

pick up EVGA G2 750W.

Legojon · 26 Sep 2014 at 19:34

CinderzFTW said:
pick up a good 850 or better to give you plenty of headroom

I like to upgrade GPUs after about 12-18 months, so want to get something that will last a couple of generations. I realise this is overkill for 2x970s, but I'm looking at the Superflower 1300 Gold. Although I believe 850w is sufficient for these cards.

I'm also really paranoid now as shortly after I fitted the 970s, the computer started switching itself off, followed by a memory stick failing (which I've now replaced - but still switching off). So I want to swap the PSU before I do any further damage and hope its not too late for the rest of my system!

CinderzFTW · 26 Sep 2014 at 19:51

to be fair, 1300w is a massive overkill... go for a 1000w then... also got to think about your electric bill lol

krooton · 26 Sep 2014 at 19:52

Well my 750w powered 7950s with plenty of wattage to spare, and they had a TDP of 200w, whereas 970s seem to pull in the region of 160w.

Legojon · 26 Sep 2014 at 20:02

CinderzFTW said:
to be fair, 1300w is a massive overkill... go for a 1000w then... also got to think about your electric bill lol

I was originally going to go for the 1000w, but the 1300w is only £10 more.

krooton said:
Well my 750w powered 7950s with plenty of wattage to spare, and they had a TDP of 200w, whereas 970s seem to pull in the region of 160w.

Is that for reference cards at stock speed though? I plan on running the MSI cards at 1500mhz, so I'm guessing that will increase the power draw significantly. If I can dig out the article, I'm sure I've seen graphs of 970s at 1500/8000 drawing more than 200w.

krooton · 26 Sep 2014 at 20:06

Legojon said:
Is that for reference cards at stock speed though? I plan on running the MSI cards at 1500mhz, so I'm guessing that will increase the power draw significantly. If I can dig out the article, I'm sure I've seen graphs of 970s at 1500/8000 drawing more than 200w.

Even so, the rest of your machine is hardly going to be pushing the limits.

Legojon · 26 Sep 2014 at 20:42

krooton said:
Even so, the rest of your machine is hardly going to be pushing the limits.

Ah right. I see what you mean. I wish the psu prices were spaced a bit more evenly though.

barmyllama · 26 Sep 2014 at 22:25

Running 2 GTX 970's, with a 750 watt SuperFlower PSU. No problems at all.

970's only draw 150 watts each, most modern CPU's don't use more than 100 watts. So if everything else drew another 100 watts (very doubtful you could draw that much) then a 750 is plenty.

pandem0nium · 26 Sep 2014 at 22:55

CinderzFTW said:
to be fair, 1300w is a massive overkill... go for a 1000w then... also got to think about your electric bill lol

Going for a higher rating psu doesn't mean higher bills, thats not how it works. If your machine requires 500w, thats what it'll draw from the wall (plus a bit depending on the efficiency) regardless of whether you're running a 600w or a 1500w psu.

Jono8 · 26 Sep 2014 at 23:00

I would be happy with anything over 750 watts.

AthlonXP1800 · 29 Sep 2014 at 18:09

Go for 750W or higher if you planning to OC both GTX 970 cards to 1.5GHz as it added about 60W.

SoulWings · 29 Sep 2014 at 19:37

850w is enough if you are planning to OC, and still have some headroom.

Legojon · 30 Sep 2014 at 22:51

Yep. My problems were psu related. Low frame rates plus computer switching off. Computer is perfect now with cpu and both gpus overclocked. I wouldn't feel comfortable going lower than 850 to allow for overclocking.

NexusK · 1 Oct 2014 at 13:04

Even a good 650w will power 970 sli fine in a stock system, 750 is plenty.

russell664 · 1 Oct 2014 at 13:24

750w is loads, just be sure to get a quality unit.