I went to the shop and asked for a motherboard that will support my PCi Express 2.0 graphics card. They sold me a board that has 1 x pci express x16 slot that conforms to pci express 2.0 standards. Does this mean that my graphics card will run on this motherboard, but only at half the performance it really can or does it really run at pci express 2.0 rates?
PCI-E 2.0 graphics cards are backwards compatible with older PCI-E 1.0 slots. PCI-E 1.0 cards could also be used on PCI-E 2.0 boards.
Performance wise, probably only a 5870 or 480 would max out even the PCI-E 1.0 x16 slot. There were tests before and even an 8800GTX couldn't really max out the PCI-E 1.0 slot (as there was no gain seen when moving to a PCI-E 2.0 x16 slot).