I agree. There is no way the CPU itself is reducing the performance of your graphics card.
It might be that it is not performing as well as it COULD be however, the CPU that is, due to not having the most current motherboard bios version installed, not having the latest chipset, audio, network controller or storage controller drivers installed (As outlined on your motherboard product page) or that you are in need of doing a clean install of windows.
These are the usual suspects when the hardware should be good enough but the system is underperforming.