A H Series mobo can't overclock using standard techniques, Intel doesn't allow it. However Asus did release a BIOS update, for some motherboards, that allow overclocking using the base-clock method (this rises the clock-speed of everything in the system, e.g. the CPU, RAM, GPU, ect). However I wouldn't suggest this as its not a very stable way of doing so.
A solution would be to buy a Z series motherboard, but that is a lot of extra effort.