I'll give 2 examples of what happens. I can be playing SWTOR just fine and when i get into a conversation with an NPC it can dip into single digit frames. It doesn't always happen just here and there. Also While playing Skyrim I can just drop to very low FPS for no reason and I mean like nothing going on. No massive battles or anything like that.
Now the strange thing is it's always fixed by alt+tabbing out and going back into the game. Doing that puts me right back to 60 fps. But until I alt+tab out, my frames take a massive drop and stay there.