No matter how powerful your CPU is, a GPU is much better for mining. A friend has that CPU, but it's all in the GPU. You'll need to invest in a motherboard that can handle many PCI slots, that way you can feed it more graphics cards.
You don't need to worry about the bus speeds and stuff like that, as all the work is done on the graphics cards, and it's minimal data being transmitted over once the work is completed.
Thanks for the suggestion, @la7me. This build is not for gaming and mining. I will update the information soon for those porpose.
Ah sorry, I misread GHz for gigahash :D