To get right to the point, upgrading from PCI Express 1.x to 2.0 is not worthwhile right now. The current crop of graphics cards just doesn't tax the PCI Express bus enough for a difference to be visible. All test cards, across the board, showed a minor performance boost of 1 to 2 percent, with the HD2900 XT reaching better results despite the fact that it doesn't have a 2.0 interface. This improvement may be caused by the newer chipset or the higher memory speed. Also, a difference of 1 to 3 percent is also slim enough to be considered within the margin of error for testing.

It remains to be seen what the situation will be when newer graphics cards such as the Geforce 9 or the Radeon 4xx0 begin transferring larger amounts of data over the bus. At any rate, the P35 and 975 chipsets are easily sufficient for the current generation of cards.