Upped the vcore by 0.01v this morning and ran it in Vista this time. Failed after 5 hours.

Trying again with another 0.01v. If that falls over then I'll play with the NB voltage again. I've already had to up the NB to 1.52v for 3.8ghz.

I'm dreading to think what NB voltage I'll end up at when I'm trying it with 8gb installed.