My DS3 wont overclock anymore!

I have had my DS3 OCed to 2.8ghz for the last 2 months until a couple days ago I turned tried to turn it on and it rebooted back to the default 1.8ghz. I have tried to reoverclock it(also with lower OCs), but it gets to the POST screen then reboots back to default clocks. I have all the voltages set to wusy's guide. I ran memtest-it passes. I updated the bios from f9 to f12(after the problem started). The temps are all ok-idle~25C.~. The system will boot fine at the stock settings. I have had no hardware changes in the last month. I tried setting the pci express at 102mhz as recommended by a few post. Do you guys have any other ideas?

Thanks for the reply, I also posted this question in the CPU section and some one gave me advice to unplug USB drives as a solution and it worked but I didnt know why- now I know.Thanks, and welcome to the forum!

Your system voltage probably varies due to the board's default settings to raise and lower your CPU clock depending upon the CPU's demands. EIST I think it's called.

You might also have that feature enabled that overclocks automatically dependant upon hardware demands.

Monitor the clock speed with CPU-Z.