Any function for estimating how hard the CPU is working?

I am porting my Oblivion Safe Save Auto Gamesave Mod and need a way to detect when "a lot is going on" in the game.

I use FRAPS for taking screenshots and getting frame rates.

To get the memory being used, start the game, Alt + Tab out to the desktop, use CTRL + ALT + DEL to open Task Manager, go to the Performance Tab, then click on the Resource Monitor button at the bottom. It will show you how the memory and cpu usage for everything running.