GeForce 6800GT gaming
We'll get right down to gaming with the GeForce 6800GT cards. This may be a better chipset comparison than the Radeon gaming tests because of the different clock speeds between Radeon X600 XT and 9600 XT. Remember, though, that in this case the GPU is talking to PCI Express through a bridge chip.
We've kept the game resolution low in order to give the chipsets and PCI Express a chance to work their magic. At higher resolutions, we'd run into the limitations of the GeForce 6800GT card's fill rate, memory bandwidth, and pixel shader performance, obscuring the impact of PCI-E and the new chipsets. I've tested both UT2004 and Far Cry at medium and high quality settings, to see if larger texture sizes or additional vertex and command traffic will strain the AGP bus and allow PCI Express to excel.
Unreal Tournament 2004
Quake III Arena