Well, that has to be the "upgrade" from my beloved Asus P6T (Socket 1366 ftw!) to an Asrock Extreme6. At that time i went for a SSD (Corsair Force GT) and thought i had to buy a board with Sata 6Gb/s.
Big Mistake. For some reason, I just can't have my boot device on any Sata III port, because it just would not load windows. So, I'm again back to Sata II. In terms of overclocking stability it was pretty much a downgrade, but i still managed to get my i7 920 up to 3,8Ghz (C0).
For now i'm still using it, waiting for haswell and to get the last bit of money for it (depending on how much the new components will cost^^)