Here is what I suspect is happening.
The way you're oveclocking is by punching up the Speedstep (i.e. Turbo mode) numbers, unfortunately Speedstep doesn't work on X79 Hackintoshes, so the computer is never actually going into turbo mode and you're stuck at your base clock rate.
The way you should over clock a Hackintosh is by increasing the Base Clock multiplier from 33 to 42 and up so that the CPU is always running at your desired clock. Not the most energy efficient unfortunately, but it's the way it works on X79 machines.
My supposition could be wrong, and in that case I have no idea why your machine isn't OC-ing correctly.