"Delayed Write Failed" errors when you use the /3GB switch in Windows XP Professional

If you use the /3GB switch in the Boot.ini file on a Microsoft Windows XP Professional-based workstation, and the workstation is configured with certain graphics adapters, Windows may exhaust the memory that is available for kernel services. Therefore, Windows disk services may fail with unrecoverable file system corruption, and you may receive "Delayed Write Disk" error messages that are similar to the following: The problem may occur shortly after Windows is started.

The problem may occur if the graphics adapter on your Windows XP Professional-based workstation consumes many system page table entries (PTE), and sufficient memory addresses are not available for the Windows kernel.

Service pack information

To resolve this problem, obtain the latest service pack for Microsoft Windows XP. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.


Note This hotfix resolves the problem of data corruption that may occur if you use the /3GB switch on a Windows XP Professional-based workstation that is configured with a graphics adapter that consumes many system page table entries. However, the hotfix does not resolve performance issues that are caused by a graphics adapter driver. To resolve performance issues that are caused by a graphics adapter driver, contact the manufacturer of the graphics adapter to determine if updated drivers are available.

For information about how to contact manufacturer of the graphics adapter, click the appropriate article number in the following list to view the article in the Microsoft Knowledge Base:

You may be able to work around this problem by using the /USERVA=2944 Boot.ini option to reduce the available user memory address space.

For additional information about the /USERVA switch, click the following article number to view the article in the Microsoft Knowledge Base:
Note This setting should produce over 90 KB of free system PTES. This should be enough to satisfy any operating system, database and backup usage.
Important Microsoft Product Support Services strongly recommends using a range of memory for the /USERVA switch that lies within the range of 2900-3030. This range is wide enough to provide a large enough pool of system page table entries for all currently observed issues.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Microsoft Windows XP Service Pack 2.

For more information about the standard terminology that is used to describe Microsoft software updates, click the following article number to view the article in the Microsoft Knowledge Base: