Asus 680 gtx full 3.0 bandwidth?

I was looking to get the 3 pci slot asus 680 from new egg and was upgrading from 550 ti SLI, and was wondering if the asus 680 uses a full 2.0 pci slot, I know it's 3.0 but my mobo is only 2.0, yes I know it's compatible I'm just wondering if the 680 would preform better on a 3.0 or if no current market gpu's even use 2.0 to its full bandwidth, thanks for all the help!!!