Vista's ram works the way it should, caching everything it can so that you can quickly load apps etc.
If you then need access to the memory, for instance to run Vue or play a game it releases that cached memory back, it is quick and effecient at doing this and something I very much like about Vista.

Also and to my cost make sure your motherboard can actually support 8GB or more of ram, some say they do but actually don't, also some may support more but are very funny regarding the type of memory in the machine, i.e. they want the same brand, speed etc.

HTH
Jon

DA Portfolio - http://jonj1611.daportfolio.com/