Major Johnson: I have a 7900GS which I would suspect is very similar to your video card. I bought the following 500W PS specifically to use with it and it does just fine. Wanted to ask if your PS provides a power cable to the video card itself (that is IF your 7800GS also HAS a PWB surface connector for a direct power connection) in addition to the power to the PC-Express bus? If not, could be a reason for voltage drops at higher currents on the bus. This Rosewill has a multitude of power outputs and is currently on sale for $48 and free shipping which is less than I paid for it. I run 2G RAM, a TV receiver card, and a sound card plus four drives counting the HD so have quite a bit of power requirement and the PS handles it all fine.....Skipbo
http://www.newegg.com/Product/Produc...82E16817182044