I could be wrong but I'm pretty sure 1.56v is too high for a sandy bridge processor, I think max recommended volts is around 1.4v. Also I'm not a fan a Asus AI suite, if you want a good overclock I would recommend using the UEFI (bios) and manually adjusting all your settings for overclocking, at least that way you can control how much voltage your putting to your CPU. Also I've heard of other i7 2600K owners reaching 5.0GHz with volts well under the 1.5v mark.