I'm currently doing a run at 45x100 at 1.28v with LLC on extreme. I tried it on 75% though Prime95 stopped within 2 minutes. After putting it on 100% it's stable. I'm trying to see what the lowest voltage I can get on 45x100 is. Also notice that CPU-Z is showing 1.31v while my BIOS is 1.28v, overshooting it by a fair amount I feel. Would it be worth my while picking up some new TIM for the H100i block? I'm still using the stuff that came with it, more than six months ago.
Prime95/Custom Blend, 15 min, 1600mb (not 90%)
1 minute in and temps jumped from 45c idle to 81c.
2 minutes in and it shot up to 89/93c
3 minutes in and it dropped back down to 88c.
6 minutes in and it went up to about 92c.
11 minutes in and it's back down to 82c.
20 minutes in and it's hitting the threshold/limit.
Your cpu vcore in cpuz is what matters, the fact that its 1.28v in bios but 1.31v in cpuz at load means you are using incorrect LLC setting, or if your using offset, means you need to alter the offset. Your vcore in cpuz should be at or just below what you set in bios. A few increments lower in cpuz is to be expected, but if its way off i.e 1.300v in bios but 1.25v in cpuz that means you need to adjust the LLC level.
The fact your prime stopped at 75% LLC but works at 100% leads me to believe its starved of voltage. You are correct CPU PLL voltage can change things, and it might enable you to use slightly less vcore, but not by much.
As twocabs has already said, you will need to delid this cpu if your planning on going for 5Ghz. Its just not possible to get that high unless you have a super golden cpu that requires less than like 1.300v for 5ghz.
Edit: Also worth noting your cpu will keep heating up during prime, so if its at 80/85C for the first 30 minutes it will likely break 90C or more if you run a overnight test, since the tests become harder the longer you run it. Ive often found my temps are highest at about the halfway point of a 12 hour prime95 run.
Edited by $ilent - 3/31/14 at 1:38pm