There is a feature that throttles back clock speed to avoid exceeding it's TDP.
Try disabling APM if that's an option in your BIOS.
And check the owner's manual of your MB. I wouldn't try to overclock when I can only run 4 pins into and 8 pin connector.
no my mobo has a 4 pin connector. SOME mobos have 8 pins. i cant use an 8 pin connector in my mobo its only a 4 pin