not only that, but pci-express allows for 2 separate GPUs to be placed on the same motherboard to increase video performance, i.e., if you have a board with 2 pci-e slots, you can get 2 pci-e nvidia 6800GTs, connect them with SLI (scan link interface) and you get the power of 2 gfx cards . . .
then again . . . you will NEED the power to power 2 gfx cards that are heavy power consumers