I've this problem for a long time and everything i try to do doesn't fix it.
So my problem is that after like 2-15 minutes of playing,the game starts stuttering and i get a major fps drop (usualy form 80+ fps to 1 or even 0 fps) and my ping raises up to +999,after a while my ping comes down but my game keeps running at 1 fps with a weird chopping sound(like an eletrical saw).
Then the game stops working but the stuttering and freezing keeps happening on my desktop and any task that i try to do without rebooting my PC.
Here are my system's specs:
Intel Core i5-3570k (not overclocked)
Asrock z77 Extreme6
8GB DDR3 RAM
GTX 760 (2GB usable VRAM)
XFX 550W 80+PSU
Windows 8.1