Pagefile.sys file

December 2016

The Microsoft Windows operating system stores frames of memory that does not fit into the physical memory in the pagefile.sys file. Pagefile.sys is a system file that allows running tasks even when the physical memory has been exceeded. Cleaning the pagefile.sys at system shutdown increases the performance of the system. To clean the pagefile.sys, modifications have to be made to the ClearPageFileAtShutdown key value in the Windows registry. The registry can be accessed by the REGEDIT command. Once the changes have been made, the system has to be restarted for the modifications to take effect. Cleaning the pagefile.sys system file also results in a virtual memory extension.


What is pagefile.sys


Pagefile.sys is a file that is used by Microsoft Windows to store frames of memory that do not currently fit into physical memory. This means the system can run more tasks than the memory has enough physical space for and simply swap frames in and out of the memory as required.

Virtual memory extension


This technique allows you to extend your virtual memory.

In Windows XP and 2000, you can clean the file pagefile.sys to improve its overall performance. This can be done by creating or modifying the REG_DWORD value from 1 to 0 in the registry key ClearPageFileAtShutdown. This is located here:
HKEY_LOCAL_Machine\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

To do this:
  • Open the Start menu, click Run and type: regedit
  • Locate the key and alter the value as directed above.
  • Reboot your machine


This system file is locaed under the root: C:\Pagefile.sys

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