Microsoft KB Archive/888855

= The System tool and Task Manager do not display 4 GB of RAM in Windows Server 2003 and in Windows XP =

Article ID: 888855

Article Last Modified on 6/17/2005

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APPLIES TO


 * Microsoft Windows Server 2003, Standard Edition
 * Microsoft Windows Server 2003, Enterprise Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows XP Home Edition

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SYMPTOMS
When you use Task Manager (Taskmgr.exe) or the System tool (Sysdm.cpl) in Control Panel to view the total amount of RAM on a Microsoft Windows Server 2003-based computer or on a Microsoft Windows XP-based computer, the amount that is displayed may be less than the actual total amount of RAM that is installed on your computer.



CAUSE
This problem can occur when you use some motherboard chipsets with computers that have 4 gigabytes (GB) of RAM.



RESOLUTION
To resolve this problem, install Windows Server 2003 Service Pack 1 (SP1) or Windows XP Service Pack 2 (SP2). When you install either of these service packs in this scenario, the physical address extension (PAE) kernel is automatically loaded on the computer. For more information about how to obtain Windows Server 2003 SP1, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003

For more information about how to obtain Windows XP SP2, click the following article number to view the article in the Microsoft Knowledge Base:

322389 How to obtain the latest Windows XP service pack

Alternatively, enable PAE support on the computer that is running Windows Server 2003 or Windows XP. To do this, follow these steps:

Step 1. Modify folder options

 * 1) Click Start, click Run, type explorer, and then click OK.
 * 2) On the Tools menu, click Folder Options, and then click the View tab.
 * 3) In the Advanced Settings list, click Show hidden files and folders, click to clear the Hide protected operating system files (Recommended) check box, click Yes, and then click OK.
 * 4) Locate the system partition, right-click the Boot.ini file, and then click Properties.
 * 5) Click to clear the Read-only check box, and then click OK.

Step 2. Save a backup copy of the Boot.ini file

 * 1) Locate the system partition, right-click the Boot.ini file, and then click Copy.
 * 2) Click a different folder to copy the Boot.ini file to, and then click Paste on the Edit menu.

Step 3. Change the Boot.ini file
 Click Start, click Run, type notepad, and then click OK. On the File menu, click Open. In the Look in box, click the system partition, click All Files in the Files of type box, click the Boot.ini file, and then click Open.  Locate the line that contains information about the operating system that you want to add the /PAE switch to. For example, select the following line: multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=&quot;Windows Server 2003, Enterprise&quot; /fastdetect   At the end of the line, type /PAE. The line will appear similar to the following: multi(0)disk(0)rdisk(0)partition(1)\WINDOWS=&quot;Windows Server 2003, Enterprise&quot; /fastdetect /PAE </li> On the File menu, click Save As, click Save, and then click Yes.</li> Quit Notepad, and then restart your computer.</li></ol>

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MORE INFORMATION
For more information about PAE support, click the following article numbers to view the articles in the Microsoft Knowledge Base:

291988 A description of the 4 GB RAM Tuning feature and the Physical Address Extension switch

833721 Available switch options for the Windows XP and the Windows Server 2003 Boot.ini files

If you add more memory to the system, it is possible that the BIOS will recognize the full amount of physical RAM that is installed in the server but that Windows will recognize only a part of the RAM. If the server has a redundant memory feature or a memory mirroring feature that is enabled, the full complement of memory may not be visible to Windows. Redundant memory provides the system with a failover memory bank when a memory bank fails. Memory mirroring splits the memory banks into a mirrored set. Both features are enabled or disabled in the BIOS and cannot be accessed through Windows. To modify the settings for these features, you may have to refer to the system user manual or the OEM Web site. Alternatively, you may have to contact the hardware vendor.

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.

Additional query words: Iwill

Keywords: kbtshoot kbprb KB888855

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