Your GPU is most likely causing the isues. Have you dusted out the GPU? If not do that, it may help. Is your new CPU overclocked?
Some time ago yes, but its not very dirty. GPU is stock and never exceeds 46 C. Problem occurs with CPU running stock speed or at slightly clocked, never exceeding 55 C.
I just downloaded Gainwards EXPERTool, I wonder if it would help to clock it down a bit? I just tried Crysis again with GPU cooler running at 100% all the time via EXPERTool. No change.