As my last piece of advice, if stutter occurs and is NOT temperatures, which you can check with
You just play and records the highest temperature reached by the CPU, now if you think it's the GPU
Now, if the temps are high and the CPU is clean (which you should check), it can be the thermal paste
Now if the temps AREN'T high and you're still stuttering, next thing to check is HDD (hard disk drive)
Any annoying viruses around can slow down your PC into oblivion
And that's as far as my "blind knowledge" goes, i can't see the problems with my eyes so it's much harder to pinpoint them, i hope you understand.
Cheers and best of luck