I am dealing with a similar issue right this moment. I have been attempting to overclock my Alienware 15 R2 a little over 4 months now. I have found stable clock speeds and, settled with them still attempting to push this beast to it's max. It is on it's last leg as is. Processor and GPU probably need another pasting otherwise the board is good however; physically the same could not be said. Anyhow i am trying to utilize the boards lifespan, am at the highest stable clock I have achieved in a very long time I have been fighting with P-State issues. It has been throwing a no load perfcap when benchmarking, as well as constant fluctuations between P0 and P8. While in P8 it is a constant shift between 135mhz and 405mhz. Will let you know if I come to a solution.