Stork's Thunderbolt Build: i5-3570K | GA-Z77X-UP5-TH | HD4000 | Mountain Lion
Is speedstep working properly for you? I've got the same CPU and board and have been having some trouble. Using MacPro3,1 the P-state is stuck at 36, and iMac12,2 it's stuck at 38... Seems like I'm missing something.