28Jun/110
Windows 2003 R2 Enterprise 32-bit not seeing all available RAM
I ran into an issue today after adding more RAM to a Windows 2003 R2 Enterprise server. I upgraded it from 4GB to 20GB, but Windows still only saw around 3.25GB after booting. I checked the HP management board and it showed 20GB installed and working. After some googling, I found a solution here. Edit the boot.ini file and add a /PAE switch to enable Physical Address Extension. After rebooting, the System Properties dialog now shows a nifty Physical Address Extension line under the Computer section and all 20GB of RAM is available.