DGLee is onto something. Asus has even given him a new BIOS to try out. Disabling 4 core modules, in some cases, gives +20% performance.
He also thinks that if you have Windows recognize the cores in odd and even order(cores 0,2,4,6, then 1,3,5,7) it will be faster, but in current form, the cores are read in order. 1-8.