I have a bfg gtx 280, I tried to put it on a stock computer. It does have an 850 watt power supply unit however that I bought from tigedirect.com though.
The computer will run and play star craft 2 for about 5 minutes with bfg gtx 280 installed, but after 5 minutes the whole computer just shuts off suddenly. This makes me believe that the 850 watt power supply isn't enough power. I installed the stock video card back in and it runs fine. The stock video card is really small and in the box came advertisements of 1000 watt and 1200 power supplies. I am thinking that the problem is that the power supply is not large enough. I know not a lot about computer building. Can you give me opinion?