The paging file is a hidden file that resides on the boot partition of a server. The Windows Operating System uses the paging file as additional random access memory (RAM). The paging file and physical memory constitute the virtual memory.
The default paging file size is equal to three times the total RAM. The primary reason for configuring such a large paging file is to have a file large enough to handle a SQL Server memory dump during a software failure.
When the paging file resides on the boot partition, Windows must perform disk read and write requests to both the system folder and the paging file. Placing the paging file on a different partition reduces competition between read and write requests. To enhance performance, Blackboard recommends placing the paging file on a different partition as well as on a different physical hard disk drive so that Windows can handle multiple I/O requests quickly.