Been looking at the Asrock Extreme3 Gen3 and an I5 2500K, but I've read that the sandybridge processors don't like 1.65V ram, which happens to be the voltage of EVERY ram-stick (Of 2GB+ Sizes) mentioned here :
from the reviews people are running this ram with 1155 2500k fine
you should not be concerned with ram voltages as the processor is unlocked. you will be ocing it by upping the multi. you will not be ocing by raising the blk affecting the memory and the whole system.