Answer ID 3135
GeForce GTX 600 series (Kepler class) and higher GPUs support PCI Express 3.0. They operate properly within the SIG PCI Express Specification and have been validated on multiple PCI Express 3.0 platforms. Some motherboard manufacturers have released an updated SBIOS to enable the Intel X79/SNB-E PCI Express 2.0 platform to run at up to 8GT/s bus speeds. We have tested GeForce GTX 680 and GTX 670 GPUs across a number of X79/SNB-E platforms at 8GT/s bus speeds, but have seen significant variation in signal timing across different motherboards and CPUs. Therefore we’ve decided to only support and guarantee PCI Express 2.0 bus speeds on X79/SNB-E with our standard release drivers. Native PCI Express 3.0 platforms (like Ivy Bridge) will run at 8GT/s bus speeds with our standard release drivers.
Though we cannot officially support or guarantee 8GT/s speeds for X79/SNB-E, you can manually enable faster 8GT/s bus speeds (at your own risk) using the following executable: force-enable-gen3.exe
If you would like to revert back to 5GT/s bus speeds you can do so by running the following command from the DOS command line: “force-enable-gen3.exe –revert”
You may download "force-enable-gen3.exe". You will need to reboot your system for the changes to take effect.