I have seen it done before, I am quite sure of that.
OK, I found out how. Follow this guide on Rainmeter.http://lifehacker.com/5828789/how-to-create-an-attractive-customized-desktop-hud-with-rainmeter
When you install the program, several things should popup on your desktop. Right click on any, go down to "illustro", then "system" and click on "System.ini".
That will give you a meter showing your CPU, RAM and SWAP usage. The SWAP file is another name for the pagefile.
You can get rid of the other box's if you want, though I advise looking a bit into Rainmeter and tinkering. Its pretty useful.