I have an HP 15 notebook with an Intel Pentium 1.99 GHz CPU. I play Arma 2: DayZ Mod and it will run fine on low for a while at about 20 fps(I know that's really low, but I'm working on a gaming PC at the moment) and after a while the frame rate just drops. It will go to like 5, and nothing will make it go back up. Heat is not the problem at all but I can't think of anything else it could be.