So this issue has been driving me nuts and I really hope someone here can help me out. I've been reading the forums/articles on this site for a long time but I've never actually posted anything.
My Phenom II x6 1045t keeps randomly deciding to underclock and undervolt itself. I have Cool 'n Quiet as well as thermal control turned off in BIOS so I know that's not the problem. I've also changed my power management settings in Windows to high performance, still doesn't solve the issue. If I reboot, it will be fine for awhile but then drops down within half an hour no matter what I do.
I have not overclocked this CPU at all, and it has aftermarket cooling so I know it's not over heating. Coretemp reads 28c at idle and 42c under load.
The CPU is supposed to be running at 200MHz * 13.5 = 2.7GHz @ 1.3v
It drops down to 200MHz * 10.0 = 2GHz @ 1.2v
Thanks for the response, but I think I figured it out. Gigabyte mobo's come with a program called EasyTune. It's kind of like their version of UEFI BIOS. Anyway, after uninstalling that program, the issue seems to have vanished. Despite the fact that I had it specifically set to NOT underclock no matter what. but whatever.