in general, here is what you should expect from the program.
99% of the time it will be doing NOTHING.
it just sits in background taking up virtually no cpu resources and waiting.
it's only when you run some application that starts to consume your cpu that Process Tamer will kick in.
Some applications that might start to eat up all your cpu would be if you are converting a video file from one format to another, or perhaps zipping a large directory, etc.
normally when such apps use up all your cpu, it's hard to do other things, the windows on your desktop will feel very sluggish and it may even be hard to switch to other windows, because that one program is hogging your cpu.
here is where Process Tamer will kick in (informing you with a balloon tip in your system tray if you have winxp), by reducing the priority of this hogging application. As long as you don't try to do other stuff on your computer, the other process will still operate at top speed, but because the priority is reduced, it means that if other applications, like moving around on your desktop or using other applications will get higher priority from the operating system and therefore be much more responsive.