I had problems with 800 watts using 7950s and even using plain 7900s. I went to a coolermaster 1350 watt and have 0 problems ever since from anything. I burned a 600 watt and then the 800 watt and finally got fed up. This new one has two fans in it. One to push air in and one to suck it out at the back. Love it
If you just have one card ""maybe"" you will be ok but allot of problems listed about that card and not enough psu. I am planing on buying 3 of them since I have 3 slots and see what happens? I like those cards from what I have been reading and they will support my hybrid sli. My current cards don't.