
Make sure you have the right kind of motherboard for your needs. From what i recall motherboards with h67 chipset allowed you to use the integrated GPU, but didn't allow overclocking, and P67 allowed overclocking but didn't allow to use the GPU (or the other way around). Z67 motherboards were supposed to have both functionalities, but i don't know if they are out yet.
Whatever you decide, good luck

P.S. Overclocking on the Sandy Bridge used in comparison with the 6-core was very, very slight. Could have very well been left to automatic and worked under box cooling (which obviously was replaced anyway)