Maximium Memory Usage, How!

I have 512 MB on a workstation system, and I want to make the machine use the Maximum memory it can. I have many disk/memory intensive apps that should be draining the cache, so I would like any suggestions on clearing this up in Win 2K Pro. I just don’t feel I am getting the best performance out of these systems. I still get the occasional prog lock/NR, but the resources available are barely tapped. Any suggestions?