6970 CF vs. 6950 CF PSU requirements

I'm deciding whether to upgrade to either a 6950 Crossfire or 6970 Crossfire and have come across an odd result from the Extreme PSU Calculator. After entering my system data, the results came out as follows:

6950 Crossfire


6970 Crossfire


That's gotta be some kind of error, doesn't it? I thought the power requirements would be much closer. If the 6970 CF figure is right, that means it's as big a power pig as a 580 SLI.


Can anyone clear this up? I'd rather not buy a new PSU if it's not necessary to go 6970 CF.

Good quality 750 ps should fit the bill.

It is indeed wrong. A 650W PSU should be perfectly sufficient for a pair of 6950s or 6970s in Crossfire.

Thanks for the reassurance!

Just to confirm: I have CFX 6950s unlocked running 880/1300 (I know I haven't pushed them very much). My i7 920 is at 4GHz. The highest load I've seen on my machine when doing some 3dmark11 benching was 580W (from the wall, so actual DC draw is about 10%-12% less). during the combined GPU + CPU test. I have power tune set to +20% in CCC as well. A quality 750W will easily cover you.

Nice! this is exactly the thread I was looking for. I may be getting a second 6950 and going to try to unlock it.

I have a GS700 corsair powersupply which has 56amps on the 12v line, and a Corsair 750tx which has 60amps on the 12v line. So im safe? phew lol. close call.


Farkle0079 - thanks for posting that!