My son's 920 which reached 4.4 GHz (72 max vcore temp) on a Prolimatech Megashadow w/ IC Diamond 7 Karat as the TIM. The Megashadow is really no different than the less expensive Megahalems; it's it's not like ya can even see the fancy metal finish once it's installed ....... looks cool in box tho .....
He has twin Enermax Magma fans in a push pull configuration but if we had to do it over, woulda done this (Megahalems, two PWM fans, IC TIM and Y cable PWM splitter):