i5 6600k, EVGA GTX 970sc, ASUS Z170 Pro Gaming
I have been trying to help a friend out for over a month now with his stuttering issues. First, he was having CPU issues, turned out his AIO cooler pump was dying and caused issues, we got him a new pump and it fixed the issues being caused by his CPU. He then started having issues after the Windows 10 Creator update, after two weeks we solved those issues or we thought, the issue he is having is when playing high demanding games or while running Heaven Benchmark he gets stutters/micro stutters. At first, we thought it might be a network issue I had him to call his ISP and check everything out, they replaced his modem and router for him and he still had the issues, next we RMA his motherboard in hope it was an issue there, ASUS said nothing was wrong with his board and sent it back, I should say this was after testing RAM, PSU, HDD, SSD, and monitor. He was able to get ahold of another GPU, a GTX 560Ti I believe, with the GTX 560Ti in the system he gets no stutters in games or benchmarks. I had him to try downclocking his GTX 970 core clock and memory and if he set an offset of the clock speed to -500 his stutters go away, the issues here is I have no idea why that is the case. I had him to run AIDA64 and all of his voltages are fine, his CPU clocks never drop, his GPU clock and memory usage look fine, the only thing that changes is his GPU usage will sometimes go from 99% to 85% but that might be due to hitting a 143fps cap in the game we were testing, also his frametimes with sometimes spike around from 11ms to 19ms with some jumps to 40ms to 70ms, but his FPS never change, fps stays at 60 during the whole test with vsync on and 90-120 with it off with no large spike.
If anyone might know the issue he is having, a way to fix this issue, or something we have yet to try please let me know, or if you know why his stutters go away if he lowers his GPU clock speed by -250 to -500, I am kind of stuck as to if it is a CPU problem or GPU.