GPU Clocks are suddenly dropping.

[GalaxyYT]

I overclocked my GTX 1060 earlier today, and I was doing some benchmarks. The overlay was the EVGA Precision X OC overlay which I prefer over MSI Afterburner since its easier to read. I tested in Unigine Valley, and I don't know if I noticed that the clocks dropped since I was overclocking at the same time as the benchmark. So, I moved on to Infinite Warfare. I went into an MP match, and all was good until suddenly my clocks dropped from 2101mhz to 1406-1807mhz, constantly fluctuating, and my framerate went down from 90 to 30. This happened every 30 seconds or so, for about 5-10 seconds each time. My thermals were okay, I think. They were sitting around 60-70. Unigine Valley pushed it to 72, however. I would really like to know how to fix this.
EDIT: I figured out it was the CPU. My FX 6300 thermal throttles as soon as my gpu clocks drop. I'm planning on getting a new cooler.

 

[Mikel_4]

1. Recheck your GPU cooler, clean and replace thermal grease.
2. Use another 6 pin or 6+2 pin, could be just bad cable.
3. Try set power target as priority, revert to factory setting > if your 1060 gas 140 watt power target, try 145 watt (increase the rest ).

 

[Rango123456]

I had an GTX 650 ti which was overclocked and the same thing happened to it, the problem was that the 6 pin cable was damaged, maybe its just a bad cable,