Rebound, maybe try to adjust your PCIE clock up or down one, SB voltage may play a part too. What kind of error / crash do you get? BSOD or just a complete freeze?

Kagula - those X58A boards aren't bad at all are they? I'm finding my way up the bclks at a low 15x multi whilst I do the criminal thing and run it on stock cooling - currently at 220x15 (218x17 was stable but vcore was needed to go further - not good on stock coolig) - how have you fared so far?