This has been happening for two days, and I have no idea why. I started to notice frame drops every few seconds in City: Skylines, and later in Stardrive 2 and GTA5. Games like Armored Warfare and World of Tanks, which are more CPU dependent don't have this problem. I launched MSI afterburner to see what was happening, and the frame drops coincided with the usage drops. I have no idea what is causing this and I can't play some of my favorite games. I have an MSI GTX 660 2GB, an i5-4670k, and 8GB DDR3 RAM.