If your computer is slow and working on high resolution softwares like Corel Draw or Photoshop or any other programs, you would have come across a message "Your virtual memory is very low" popping up on the taskbar making your computer very slow and getting freezed.
Virtual memory also called as paging file or swap file is the computer's secondary memory which is used by your operating system to act as primary memory (physical RAM). If your computer needs more memory to run the applications, the operating system will assign some portion of the hard disk space to act as primary memory.
The paging file is stored in the hard disk. It is a hidden file which your operating system uses to store data that cannot fit into the primary memory.
The paging size should be 1.5 times of the actual physical RAM size (150% of your actual RAM size). Increasing the paging file size to more than 150% of the actual RAM size does not make any difference. To increase the speed of your computer you have to increase the size of your physical memory (RAM).
To increase the virtual memory "RIGHT-CLICK" on "MY COMPUTER" and click on "PROPERTIES". Go to "ADVANCED" tab and click on "SETTINGS" under performance title. In the performance options window click on "ADVANCED" tab and click on "CHANGE" under virtual memory title. Under the custom size set the initial size value to 10 to 15% and maximum value to 150% of the physical RAM or you can enter 150% of the physical RAM value to both (initial and maximum) and click on "SET" and push "OK" button.