Also on Power Macs File Mapping means that all the needed information may not be loaded when the application is launched so it may need to be loaded from the hard drive later. VM sets aside a portion of your hard drive the same size of what your virtual memory is set to. So if your VM is set to 24 M that is 24 megabytes of hard drive space that is taken up by an invisible VM storage file. Also in my experience machines running VM seem to be a little bit more unstable and more likely to crash. Below is a table of what I see some of the advantages and disadvantages of VM VM Advantages VM Disadvantages You can run more applications at once.
Applications run slower.
It takes more time to switch between applications. Applications may launch faster because of File Mapping. Less hard drive space for your use. You don't have to buy more memory. Ram Doubler 2 has some nice features.