im looking into upgrading my computer. among other things, i want to ruin a sli setup with 2 XFX GeForce GTX 280s.

I had thought an 850W PSU would be fine and allow for a few years of aging, but according to the Nvidia website, i would need a PSU giving around 1100W. given that one of the above cards requires 620W is that a realistic estimate or a bit cautious.