RAM Booster
Avoid system sluggishness and freeze ups with this free utility.
RAMBooster is a free utility that optimizes how your computer uses its RAM, working to keep as much free as possible. It can also try and free up a specified amount if you have a program that needs more free RAM than you have available.
It’s a simple-to-use program, and seems to do a good job of managing the RAM to keep more available, supports NT/XP/Win9x/ME
Download at http://www.sci.fi/~borg/rambooster