H77 Sandy Bridge DRAM Overclocking

[Fat Dog]

Recently built a Mini ITX system for a friend. Comprises:

Asus P8H77-I (running latest BIOS)
i3-2105
Corsair XMS3 8GB (2x4GB) 1600MHz

Whatever I do, I cannot get the memory to run at anything other than 1066MHz.

Does this combo (H77+S/B) allow memory overclocking? If so, anyone got any ideas?

Thanks

EDIT: Done some research, understand it won't run at 1600 or more, but why won't it run at 1333? I also can't even change the timings.