Will a PCI Express 2.0 graphics card be bottlenecked by a 1.X motherboard slot?
Not yet. 2.0 cards don’t yet use more bandwidth than 1.x slots offer, as Mercuri said. But it’s more than just a marketing issue. They do run at a higher speed than 1.x cards/slots (2.5GHz for 2.0 versus 1.25GHz for 1.x). They just don’t use all that additional bandwidth yet. And since PCIe is both forward and backward compatible (2.0 cards work in 1.x slots and 1.x cards in 2.0 slots) there are no other situations that could affect performance, either hindering or helping. So until video bandwidth requirements actually exceed what PCIe 1.x delivers there’s no difference in performance.
