Recommend PSU for 4870 Crossfire with 4870 X2

[caveman_2]

I've had a 4870 x2 running on a be quiet 850watt psu for over a year now with no problem.

I kind friend of mine has given me his 4870 since he's upgraded and i wanna try and run them in crossfire but im concerned that my psu might not be strong enough. I only want to try this for benching and not considering using it as a permanment setup

what should I expect to see the peak power draw of this setup and 100% load

[Zeus]

Go here and calculate how much your rig will draw:

http://www.extreme.outervision.com/p...ulatorlite.jsp

I think your PSU will do.

[caveman_2]

ah thanks, that unfortunately doesnt allow me the exact setup, only 4870 or 48070 x2 in crossfire. Its a little worrying that it says a single 4870 x2 recommended min psu is 704 watt so putting another card on top of that i think will be pushing my psu over the limit

[texasreefer]

Yeah, but actual voltages are seperate from theoretical voltages. For example you have a 850w PSU, but that doesn't mean it can handle 850w...but, that works both ways. I have used my 750w PC power silencer on my quadifre rig with no problems for a couple years now. This psu is crossfire certified, and I purchased it because it has a large single rail as opposed to two or more smaller rails. I have also run triple Xfire with a 4870 (as you are considering). I found triple xfire stable in gaming , but found problems with video playback. These issues may be fixed with 10.3 drivers. If your psu has the capability of running crossfire(meaning 4x 6-8pin cables), I don't think you will have issues with your psu.

[Razrback16]

If I were you I wouldn't risk it. On my systems I try to make sure that day to day usage will not exceed 80% of the maximum PSU output. This way you have a little room in case for whatever reason you end up drawing more juice than usual (furmark, etc. if you're into that stuff). I'd upgrade to atleast a 1000W PSU. That's what I'm running and have zero issues. Better to be safe than risk frying all your sh*t.

[antiacid]

I run the same configuration of GPU's on a zalman z-850 (850watts) and my cpu is OC to 4.2ghz (a q9650) and I never have any power issues. BTW, I also run a truckload of watercooling gear and peripherals and I basically don't peak above 550-600watts anyway. I even had my cards oc'ed about 10-15% but then the heat dump in the summer in my room just made it ridiculous to game for more than a couple of hours (I guess that's nature's way of saying I should be hanging out outside or something)

Short answer: You'll be fine.

[zalbard]

Yeah, stick to what you already have.