My computer has had this problem for the past week now. For some days, its perfectly fine and runs all the games at the fps its supposed to run at. Just yesterday I was playing Dota 2, and it ran at 100 fps. Today I booted Dota 2, and it ran at 100 fps for 1 minute, and then it drastically reduced fps to 30. I noticed that shaking the computer case passively fixed the problem most of the times, but now it doesn't fix it. On the days that the fps is high, I notice that the computer case generates a vibrating sound. And on days where the fps is low, the cpu is silent. What can be the cause for this, and what is the fix? I notice that my GPU is at 80 C today, but it doesn't seem to be the cause. If you need more specifications, ask me.