In BIOS make sure Cool'n'Quiet is turned off.
Make sure C1E support is turned off
Go into Windows control panel under power options and make sure you set for maximum performance.
You set the option in bios "to all cores" and not "per core"?
Sorry if someone else said this already... didn't look previous page.
Nice little trick, didn't know that. I least I know now that all my cores are the same, and my system is O/C to 3.9Right click over the core frequency on CPUZ and see if all the cores say the same.
Does the CPU Core Control have Auto instead of Manual. If so try Auto.