1.I will check CPU cooling.
2.No way,not from my GPU,please check my video to know,you will surprise,really strange :https://www.youtube.com/watch?v=YLUX0-CeulM
3.from the video,you can see each time AUX goes over 70 degree,the game starts throttle like that,%cpu usage reduce from 90% to 5% game freeze with 0 fps