So the NVIDIA GeFroce GTX 680 was released yesterday, and they were sold out almost immediately. If you were one of the fortunate ones who were able to get your hands on one as well as a Sandy Bridge-E X79 chipset user, you may want to hold off on downloading the newest available drivers.
On GeForce.com's specifications page for the card, they list it as a PCI Express 3.0 card, but they have some small-print that says on the X79 chipset it's limited to PCI Express 2.0 speeds:
There is some good news, though. According to TechPowerUp, the drivers that ship on the disk are the pre-launch drivers that will support PIC Express 3.0 on the X79 chipset. I know it's weird to use drivers off of a disk, but sometimes that's just what you have to do. NVIDIA should release an update some time soon that will fix this limitation and allow you to upgrade drivers.