From what I understand, the PCIe 2.0 graphics cards are backwards compatible with the 16x PCIe slots. Can someone confirm this and explain if there is some sort of decrease in performance? Also, what graphics card would suit my system well to play games like COD Black Ops in a decent resolution?
PCI-e 2.0 is backwards compatible with PCI-e 1.x slots. There will be no decrease in performance. PCI-e 2.1 cards are generally not totally compatible with PCI-e 1.x slot. Some people have had problems; the argument is that some manufacturers did not implement PCI-e 1.x slots properly in some motherboards.