When your computer is running low on RAM and more is needed immediately, Windows uses hard drive space to simulate system RAM. This is known as virtual memory, and is often called the paging file. This is similar to the UNIX swapfile. The default size of the virtual memory paging file (named pagefile.sys) created during installation is 1.5 times the amount of RAM on your computer.
You can optimize virtual memory use by dividing the space between multiple drives and removing it from slow or heavily accessed drives. To best optimize your virtual memory space, divide it among as many physical hard drives as possible. When you select drives, keep the following guidelines in mind:
Try to avoid having a paging file on the same drive as the system files.
Avoid putting a paging file on a fault-tolerant drive, such as a mirrored volume or a RAID-5 volume. Paging files do not need fault-tolerance, and some fault-tolerant systems suffer from slow data writes because they write data to multiple locations.
Do not place multiple paging files on different partitions on the same physical disk drive.
To Change the Size of the Virtual Memory Paging File
You must be logged on as an administrator or a member of the Administrators group in order to complete this procedure. If your computer is connected to a network, network policy settings may also prevent you from completing this procedure.
- Click Start, click Control Panel, click Performance and Maintenance, and then click System.
- Click the Advanced tab, and then click Settings under Performance.
- Click the Advanced tab, and then click Change under Virtual memory.
- Under Drive [Volume Label], click the drive that contains the paging file you want to change.
Under Paging file size for selected drive, click Custom size, type a new paging file size in megabytes (MB) in the Initial size (MB) or Maximum size (MB) box, and then click Set.
If you decrease the size of either the initial or maximum paging file settings, you must restart your computer to see the effects of those changes. When you increase the paging file size, you typically do not need to restart your computer.