Here is the method I used and have recommended it to many people and have had it work.
First things first, set your BIOS to defualt everything.
Turn ACC on and reboot back into the BIOS.
Set your CPU voltage to 1.2v.
I know its low but trust me.
Boot up into windows.
Run Prime95 SmallFFT test for about 10-15 minutes or so to get initial stability.
If the test fails then bump up the voltage to 1.225v or so.
I was in the same position as you.
I had gone from stock volts (1.35v) up to 1.5v without success.
Then, I booted up in 1.2v and it worked.
GL
First things first, set your BIOS to defualt everything.
Turn ACC on and reboot back into the BIOS.
Set your CPU voltage to 1.2v.
I know its low but trust me.
Boot up into windows.
Run Prime95 SmallFFT test for about 10-15 minutes or so to get initial stability.
If the test fails then bump up the voltage to 1.225v or so.
I was in the same position as you.
I had gone from stock volts (1.35v) up to 1.5v without success.
Then, I booted up in 1.2v and it worked.
GL