How to Enable PAE on a 32 Bit Windows XPby Greg Lindberg ; Updated February 10, 2017
The Physical Address Extension (PAE) memory is a feature in the Windows XP operating system for supporting more than four gigabytes (GB) of memory. This is useful for users who have 32-bit (IA-32) Intel Pentium Pro platforms and later models. In order to enable PAE you must have administrator rights and be able to add the PAE switch to an entry for the Boot.ini file. Before trying to add the switch you should check to make sure PAE is not already enabled.
Check to see if PAE is enabled by clicking on the “Start” option and then by clicking on the “Run” option. Enter “sysdm.cpl” into the “Open” field and then click on the “Enter” option.
Click on the “Advanced” tab and then click on the “Settings” option from the \"Performance\" section. Click on the “Data Execution Prevention” tab and review the status message at the bottom of the dialog box to see if PAE is enabled or not.
Close out of the dialog box and then click on the “Start” option to begin the process of enabling PAE. Click on the “Run” option and then enter “notepad c:\boot.ini” into the “Open” field. Click on the “Enter” button.
Look for the “/noexecute” switch below the operating system heading and place your cursor at the end of the command. Enter a space and then “/pae” at the end of the command.
Save the file and then restart your computer. The PAE will now be fully enabled on your computer.