I have the BFG 6600GT in a Dell 4400 2.8g 400mhz FSB. It runs all new games, HL2, Battlefield 2, and Doom 3 reasonably well. All of these at lower gaphics settings of course. This is about the max I can go in this machine due to the FSB bottleneck. A 6800 would be overkill in this machine. If you have an older 400mhz FSB the 6600GT is the way to go and the BFG is the best. If you have a 533mhz or 800mhz fsb CPU then you'd be better served by a 6800 series card. It would give you the best "bang for your buckz."