Windows Server 2003 Displaying Only 3.25GB of RAM on 8GB Systems

A client of mine recently had the following issue. They had an HP ProLiant DL360 G5 server running Windows Server 2003 Enterprise edition. The server had 8GB of RAM but in the System Properties in Windows it displayed only 3.25GB of RAM. The CPU type and speed were displayed correctly and the BIOS showed the correct amount of RAM at boot.

You see memory below 4GB due to a limitation in the 32-bit operating systems. It is not specific to any brand (HP, Dell, etc.) The Physical Address Extension (PAE) is what can allow the operating system to address more than 4GB of memory. In Windows Server 2003, PAE is automatically enabled if the server is using hot-add memory devices. If you don’t have hot-add memory support then PAE is not automatically enabled and you would have to manually add the /PAE switch in the boot.ini file to take advantage of memory over 4GB.

The PAE switch needs to be added to all versions of 32-bit Windows that have more than 4GB of memory. The boot.ini should look like this.

[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

When you reboot the computer after adding the /PAE switch, you will notice that the General tab of the System Properties lists Physical Address Extension at the end of the Computer section.

Note: On x86 systems, Windows Server 2003 Standard edition only supports up to 4GB of RAM but the Enterprise edition can support up to 32GB of RAM. Windows Server 2003 R2 Standard edition also supports up to 4GB of RAM but Windows Server 2003 Enterprise R2 edition supports up to 64GB. For more detailed system requirements check out this link on Microsoft TechNet’s Web site.