All processors that are based on the IA-32 architecture,starting with the Intel Pentium Pro, support a new 36-bit physical addressing mode named Physical Address Extension (PAE). PAE allows for up to 64 GB of physical memory. PAE maps up to 64 GB of memory into a 32-bit (4 GB) virtual address space. Also, each operating system may hard-code an address limit less than 64 GB. Ffor example, there is an 8 GB hard-coded address limit in Microsoft Windows 2000 Advanced Server. The PAE mode kernel requires an Intel Architecture processor Pentium Pro or later versions, more that 4 GB of RAM, and either Windows 2000 Advanced Server,Windows 2000 Datacenter Server, Microsoft Windows Server 2003 Enterprise Edition, or Windows Server 2003 Datacenter Edition.
- Click Start, click Run, type cmd in the Open box, and then click OK.
- Type attrib c:\boot.ini -r, and then press ENTER.
- Type exit, and then press
- Click Start, click
Run, type notepad c:\boot.ini in the Open box, and then click OK.
A window opens to display the Boot.ini file..
- The line that starts with "default" is the location from which Windows 2000 Advanced Server will load on startup without user intervention. For example, the line may appear as:default=multi(0)disk(0)rdisk(0)partition(1)\WINNT
- Locate the line for Windows 2000 Advanced Server that corresponds to the information on the default line. It should look similar to the following:multi(0)disk(0)rdisk(0)partition(1)\WINNT="Windows 2000 Advanced Server" /fastdetect
- Add a space and /PAE to the end of the line. The line should now look similar to the following:multi(0)disk(0)rdisk(0)partition(1)\WINNT="Windows 2000 Advanced Server" /fastdetect /PAE
- Click the Close box to close the Notepad window, and then click Yes when you are prompted to save changes.
- Restart the system, and then verify that the correct amount of system memory is now available.
multi(0)disk(0)rdisk(0)partition(1)\WINNT="Windows 2000 Advanced Server" /fastdetect /PAE
For additional information about PAE server design, visit the following Microsoft Web sites:
For example, if you are running a system that has 4 GB of RAM installed and you then add 4 GB of additional RAM, Windows may recognize only 4 GB of physical memory or possibly 6 GB instead of the full 8 GB. The redundant memory feature or the memory mirroring feature may be enabled on the new memory banks without your knowledge. These symptoms are similar to the symptoms that occur when you do not add the /PAE switch to the Boot.ini file.
Article ID: 255600 - Last Review: Jun 11, 2009 - Revision: 1