650 PSU enough for two 7950 OC to 1050/1250?

[Makaveli]

I would go with a 750 watt psu just to have the extra buffer and as the psu ages.

 

[2is]

Can I ask why you want to do Crossfire? If you're just gaming on 1080p, one overclocked 7950 runs everything fine. If you want an upgrade at least wait until the 9000 series are out before buying another 1.5 year old card. Finally, I don't think your Phenom X6 cuts it. It's already a bit on the weak side for one 7950 in CPU heavy games. What I would do: wait for 9000 series, then upgrade to 4670K/4770K + 9950 or whatever replaces the 7950 in the product hierarchy

I think you'd probably be fine with that unit but 750W would be optimal.

I game at 1200p and adding a 2nd 680 saw some nice gains in several games. That said, I have a 3770k pushing them.

As to the original question. My 680's which are more efficient than a 7950 pulled just above 500watts from the wall while gaming. Keeping that in mind and that the X6 will also be drawing more power than my 3770k, I think you could very well be right around 600-650watts. That's from the wall so power draw from the PSU itself would be around 520 watts (assuming 80% efficiency)

And that's BEFORE we factor in over clocking of either the GPU's or CPU... I'd say you'd be cutting it very close.

 

[spat55]

The CPU would bottleneck more than one so don't bother.