I use this freeware (it is commercial in ways, it is just that you as an individual can use it for free) memory management software called Cacheman - I pretty much have to because I have 512MB of RAM in Windows 98, and you need such a program to get the excess RAM to be handled properly anyway.
In addition to helping you monitor your RAM/virtual memory/etc usage at any given time, it can also free up memory either automatically or by telling it to do it manually, and has various profiles and settings to optimize how your computer deals with things like cache, RAM, and virtual memory. I never have it off, and never have a problem with it.
Heres the site (they have lots of other neet tools and such too, but I just mainly use Cacheman):
http://www.outertech.com/
...oh, and no, I'm not affiliated with them in any way other than using their product
"My house has a 3D interface. I'm constantly losing crap, running into things, and it's always a mess."