Exactly as nasomi says your looking for changes that would fit in with the issues, the gpu/cpu spiking or dipping to near max/min and so on.

A simple test would be to log in while recording, cast a spell or 2 wait 30s do it again 2-3 times log out and look at the log for a pattern.
If thier is take a sceen shot showing us and well have a look at what to do next.

Also see if you have Speedstep (power management for the cpu, lots of guides to turning it on/off) enabled, a few people had issues around it and after turning it off had much better performance in games.
(It was what i was thinking off that messes up the cpu not the turbo feature)