On a multiprocessor system that is running a 64-bit version of Windows Server 2003, CPU 0 approaches a 100-percent "CPU Usage" reading earlier than do other CPUs on the system

On a multiprocessor system that is running a 64-bit version of Windows Server 2003, CPU 0 approaches a 100-percent CPU Usage reading earlier than do the other CPUs on the system. A tool such as Performance Monitor may show that much of the CPU 0 resources are used at the Deferred Procedure Call (DPC) level. You do not receive an error message.

Although this problem may occur on smaller symmetric multiprocessing (SMP) systems, you are more likely to notice this problem in larger SMP systems that use at least four CPUs. Additionally, you are likely to notice this problem only when the system is experiencing a heavy workload, such as during performance testing.

This problem occurs only when there are at least 24 timers outstanding in the system for an extended period. Timers are used by the Windows operating system, by device drivers, and by applications that explicitly use timers or that specify timeouts in applicable system calls.

Service pack information

To resolve this problem, obtain the latest service pack for Windows Server 2003. For more 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.

Prerequisites

You must be running one of the following operating systems to install this hotfix:

• Microsoft Windows Server 2003, Datacenter Edition for Itanium-based Systems SP1
• Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems SP1
• Microsoft Windows Server 2003, Datacenter x64 Edition
• Microsoft Windows Server 2003, Enterprise x64 Edition
• Microsoft Windows Server 2003, Standard x64 Edition

Restart requirement

You must restart your computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes. However, because this hotfix replaces the Windows kernel (Ntkrnlmp.exe), this hotfix may override other previous Windows kernel replacements.

File information

The English version of this hotfix has the file attributes (or later file attributes) 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.

Windows Server 2003, x64-based versions

Windows Server 2003, Itanium-based versions

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 Windows Server 2003 Service Pack 2.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Technical support for Windows x64 editions

Your hardware manufacturer provides technical support and assistance for Microsoft Windows x64 editions. Your hardware manufacturer provides support because a Windows x64 edition was included with your hardware. Your hardware manufacturer might have customized the Windows x64 edition installation with unique components. Unique components might include specific device drivers or might include optional settings to maximize the performance of the hardware. Microsoft will provide reasonable-effort assistance if you need technical help with your Windows x64 edition. However, you might have to contact your manufacturer directly. Your manufacturer is best qualified to support the software that your manufacturer installed on the hardware.

For product information about Microsoft Windows XP Professional x64 Edition, visit the following Microsoft Web site: For product information about Microsoft Windows Server 2003 x64 editions, visit the following Microsoft Web site: