Dell precision m6600 cpu being throttled. Tried everything.

Hi I have a Dell precision m6600. It starts of great then after a few minutes it gets extremely slow. It takes one or two restarts before it starts running great again. But after a few minutes it will throttle again. 

Its not heat: I've been monitoring the heat. Temp stays around 50*Celsius most of the time. I also recently replaced the thermal paste while I replaced the cpu and gpu.

Its not power management: i made sure its set for performance. Minimum cpu is set at 100. Max at 100.

I also disabled power throttling through local group policy.

I also enabled hyperthreading and any cpu boosting available through the bios. 

Im stomped. Besides the obvious slowdown userbenchmark.exe also states that my cou is being throttled 34% by windows.

Im at my wits ends. Someone please help with ideas.