2 monitors works a treat for this type of thing!
Are there any apps that display CPU usage onscreen during a game? Kinda like an FPS monitor but for processors.
I'm currently trying to work out what to upgrade first, mobo\cpu\ram or graphics card.
If you want to know your cpu usage, why not alt tab and check windows task manager.
The problem with that is cpu usage may well be very different when you are alt-tabbed; many games seem to pause automatically when they lose focus for example. OK so you can track history on the graph but you can't take a snapshot at a particular moment.