PAE switch is the added ability of the IA32 processor to address more than 4 GB of physical memory. The following operating systems can use PAE to take advantage of physical memory beyond 4 GB:

Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Datacenter Server
Microsoft Windows Server 2003, Enterprise Edition
Microsoft Windows Server 2003, Datacenter Edition
To enable PAE, use the /PAE switch in the Boot.ini file.

The following is an example of a Boot.ini file where the PAE switch has been added:

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Windows Server 2003, Enterprise" /fastdetect /PAE

Note: In Windows Server 2003, PAE is automatically enabled only if the server is using hot-add memory devices.