So here is a strange thing that I can't find much info on and have no idea why it happens: When I enable LLC (setting enabled as opposed to auto) on my Asrock 970 Extreme3 (BIOS version 1.40) with a 955 Phenom II in it, the comp boots and initial CPU voltage appears normal (in fact, it is closer to what I set in BIOS than with it off). but, when I put a load on (such as a prime95 test), the voltage starts to DROP.
There seems to be some kind of rate limit on how fast it can change in either direction, but the voltage goes down... and down... and down. I'm not talking about just a little, I mean on the order of a 0.25V drop. Before I BSOD with LLC on, the lowest voltage I have seen it hit was 1.12V from a BIOS set voltage of 1.3375.
The exact opposite happens when I set LLC to disabled in BIOS. My initial voltages are higher (setting 1.3375 yields a BIOS HW monitor reading of 1.352V), and when I load the CPU with prime95, the voltages go UP. BIOS setting of 1.3375V yields a max voltage under max load of 1.375V as reported by both AIDA64, CPU-Z, and Asrock's tuner utility. All the software has exactly matched what the BIOS HW monitor shows for CPU voltage.
This behavior seems to be exactly the opposite of what I would expect. Has anyone else seen behavior like this?
PS: With LLC off and the load voltages going up, I am prime95 stable after 6 hours (longest I have run it, I don't like testing hardware while I sleep just in case). With LLC on and the voltages dropping under load, I error out on core 4 after 5 seconds to 2 minutes max.
EDIT: I meant to post this in a new thread on the AMD mobo forums, my bad.