I have 2 saffhire hd 5770 graphics cards. One card has a sticker on the front (Black/Vision/AMD) with PCI express 2.1. The other card is a CPI Express 2.0 and doesn't have the sticker on the front (Black/Vision/AMD). Can I use these in crossfire? If so, what to I have to do...driver updrage for pci 2.0? Also, do I use 1 or 2 crossfire bridges?