This tweak applies to Windows Vista or XP. If you are running many applications, especially large resource hogs that eat huge amount of memory your system may become unstable or even crash. You can increase the total amount of memory in your system with a simple virtual memory tweak adjustment. If your PC already has more than 3 GIG of RAM you dont really need a page file, this tweak is mostly for those who have less than 2 Gig of RAM.
Set the "Maximum and Min size (MB)" to the same size , this will prevent it from growing on your hard drive. Set the size to 1.5x (multiply) times the size of your physical RAM.
Example if you have a PC with 2 Gigs of Ram, set the Pagefile size to 3000 Meg. Also remember that a pagefile is on the hard drive which is slower than RAM, so the more your system uses a paging file in some cases it may be slower.