By default 32 bit Windows installs will not be able to utilize more than 4GB of memory. However PAE (Physical Address Extension) can be enabled which allows the OS to see memory beyond 4GB. Note that each individual process is still limited to 4GB of memory, even if the OS can see more than that. The only solution to allow a single process to access more than 4GB is to upgrade to a 64 bit OS.

1. Click Start -> Control Panel -> System

2. Select the Advanced tab

3. Click Settings under “Startup and Recovery”

4. Click Edit

5. The boot.ini file will open in Notepad for editing. The last line of this file should look something like this:

multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows Server 2003, Standard" /noexecute=optout /fastdetect

Just add “/PAE” to the end of this line so it looks like the example below:

multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows Server 2003, Standard" /noexecute=optout /fastdetect /PAE

6. Save the file and click OK twice

7. Reboot the server to apply the change.

Even with PAE enabled the OS still has a memory limit. To see the limit for a specific Windows release please refer to:
Memory Limits for Windows Releases

In this example the server is running Server 2003 Standard which has an OS limit of 4GB so enabling PAE would not help. This was just done for demonstrative purposes.

One Response to “Enable PAE on 32 bit Windows”

  • Sam Kaigler says:

    Dude…..YOU ROCK!!

    I have been scouring MS website trying to find the PAE instructions……nothing as straightforward as this.

    Worked great, thanks!

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