Windows Virtual Memory Paging File

When your system gets low on virtual memory (for example when you start running antivirus software), Windows will automatically try to increase the size of your virtual memory paging file. The idea is to supplement the physical RAM available to the system with "virtual RAM". The size of this virtual RAM is set by Windows to be 1.5 times physical RAM. Accessing the paging file makes more memory available but slows the system down due to disk accesses. It used to be possible, and often necessary, to expand virtual memory using 3.5 inch disks on Windows. You can't really do this trick with CD-RW or DVD-RW, which have much shorter rewrite cycles than all previous storage media.