Hey Mandala - Not sure about the "when using resource hungry programs" bit...I don't think there is any freeware available specifically for that. The games though, I can help with. IObit, the makers of Advanced SystemCare and other very good products have a specialist freeware just for that called Game Booster.

It works by defragmenting game directories, temporarily shutting down background processes, cleaning RAM, and intensifying processor performance. You can read more about Game Booster and download from here: http://www.iobit.com/gamebooster.html

cheers....JIM