You encounter a decrease in I/O performance under a heavy disk I/O load on a Windows Server 2008 R2-based or Windows 7-based computer

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Article ID: 982383 - View products that this article applies to.
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SYMPTOMS

The performance of a computer that is running Windows Server 2008 R2 or Windows 7 decreases by 20 percent under a heavy disk I/O load.

This issue usually occurs on a computer that has more than 8 processors.

RESOLUTION

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 the problem described in this article. 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:
http://support.microsoft.com/contactus/?ws=support
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

To apply this hotfix, you must be running Windows 7 or Windows Server 2008 R2.

Registry information

To use the hotfix in this package, you do not have to make any changes to the registry.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

File information

The English (United States) version of this hotfix installs files that have the attributes that are listed in the following tables. The dates and the times for these files are listed in Coordinated Universal Time (UTC). The dates and the times for these files on your local computer are displayed in your local time together with your current daylight saving time (DST) bias. Additionally, the dates and the times may change when you perform certain operations on the files.
Windows 7 and Windows Server 2008 R2 file information notes
Important Windows 7 hotfixes and Windows Server 2008 R2 hotfixes are included in the same packages. However, hotfixes on the Hotfix Request page are listed under both operating systems. To request the hotfix package that applies to one or both operating systems, select the hotfix that is listed under "Windows 7/Windows Server 2008 R2" on the page. Always refer to the "Applies To" section in articles to determine the actual operating system that each hotfix applies to.
  • The MANIFEST files (.manifest) and the MUM files (.mum) that are installed for each environment are listed separately in the "Additional file information for Windows Server 2008 R2 and for Windows 7" section. MUM and MANIFEST files, and the associated security catalog (.cat) files, are extremely important to maintaining the state of the updated component. The security catalog files, for which the attributes are not listed, are signed with a Microsoft digital signature.
For all supported x86-based versions of Windows 7
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File nameFile versionFile sizeDateTimePlatform
Ntkrnlpa.exe6.1.7600.206853,955,08007-Apr-201007:38Not Applicable
Ntoskrnl.exe6.1.7600.206853,899,78407-Apr-201007:38Not Applicable
For all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Ntoskrnl.exe6.1.7600.206855,484,94407-Apr-201007:51x64
Ntkrnlpa.exe6.1.7600.206853,955,08007-Apr-201007:38Not Applicable
Ntoskrnl.exe6.1.7600.206853,899,78407-Apr-201007:38Not Applicable
For all supported IA-64-based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameFile versionFile sizeDateTimePlatform
Ntoskrnl.exe6.1.7600.2068511,116,43207-Apr-201006:19IA-64
Ntkrnlpa.exe6.1.7600.206853,955,08007-Apr-201007:38Not Applicable
Ntoskrnl.exe6.1.7600.206853,899,78407-Apr-201007:38Not Applicable

WORKAROUND

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
To work around this issue, add the following registry entry to the registry, and then set the value to 1:
Location:  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\kernel
Name:  MaximumDpcQueueDepth
Type:  REG_DWORD
Value: 1

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

For more information about the organization of the DPC queues, visit the following website:
General information about the organization of the DPC queues
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:
824684 Description of the standard terminology that is used to describe Microsoft software updates

Additional file information

Additional file information for Windows 7 and for Windows Server 2008 R2

Additional files for all supported x86-based versions of Windows 7
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File nameUpdate.mum
File versionNot Applicable
File size1,674
Date (UTC)07-Apr-2010
Time (UTC)11:33
File nameX86_47a3171ee4a15500c8d9365c407ee7dc_31bf3856ad364e35_6.1.7600.20685_none_655336761f0e1360.manifest
File versionNot Applicable
File size697
Date (UTC)07-Apr-2010
Time (UTC)11:33
File nameX86_microsoft-windows-os-kernel_31bf3856ad364e35_6.1.7600.20685_none_6c90585b2e9441f1.manifest
File versionNot Applicable
File size16,151
Date (UTC)07-Apr-2010
Time (UTC)08:09
Additional files for all supported x64-based versions of Windows 7 and of Windows Server 2008 R2
Collapse this tableExpand this table
File nameAmd64_0a3952afcd841f6ab7eee2ca22bcaaf8_31bf3856ad364e35_6.1.7600.20685_none_37e35d8dad5b9f77.manifest
File versionNot Applicable
File size701
Date (UTC)07-Apr-2010
Time (UTC)11:33
File nameAmd64_47a3171ee4a15500c8d9365c407ee7dc_31bf3856ad364e35_6.1.7600.20685_none_c171d1f9d76b8496.manifest
File versionNot Applicable
File size699
Date (UTC)07-Apr-2010
Time (UTC)11:33
File nameAmd64_microsoft-windows-os-kernel_31bf3856ad364e35_6.1.7600.20685_none_c8aef3dee6f1b327.manifest
File versionNot Applicable
File size15,291
Date (UTC)07-Apr-2010
Time (UTC)09:11
File nameUpdate.mum
File versionNot Applicable
File size1,906
Date (UTC)07-Apr-2010
Time (UTC)11:33
File nameX86_microsoft-windows-os-kernel_31bf3856ad364e35_6.1.7600.20685_none_6c90585b2e9441f1.manifest
File versionNot Applicable
File size16,151
Date (UTC)07-Apr-2010
Time (UTC)08:09
Additional files for all supported IA-64-based versions of Windows Server 2008 R2
Collapse this tableExpand this table
File nameIa64_47a3171ee4a15500c8d9365c407ee7dc_31bf3856ad364e35_6.1.7600.20685_none_6554da6c1f0c1c5c.manifest
File versionNot Applicable
File size698
Date (UTC)07-Apr-2010
Time (UTC)11:33
File nameIa64_cf0a0e54b2032d7412234572dfef8d07_31bf3856ad364e35_6.1.7600.20685_none_dbb6268a84c2e7e6.manifest
File versionNot Applicable
File size699
Date (UTC)07-Apr-2010
Time (UTC)11:33
File nameIa64_microsoft-windows-os-kernel_31bf3856ad364e35_6.1.7600.20685_none_6c91fc512e924aed.manifest
File versionNot Applicable
File size15,289
Date (UTC)07-Apr-2010
Time (UTC)09:09
File nameUpdate.mum
File versionNot Applicable
File size1,684
Date (UTC)07-Apr-2010
Time (UTC)11:33
File nameX86_microsoft-windows-os-kernel_31bf3856ad364e35_6.1.7600.20685_none_6c90585b2e9441f1.manifest
File versionNot Applicable
File size16,151
Date (UTC)07-Apr-2010
Time (UTC)08:09

Properties

Article ID: 982383 - Last Review: June 10, 2010 - Revision: 2.0
APPLIES TO
  • Windows 7 Enterprise
  • Windows 7 Home Basic
  • Windows 7 Home Premium
  • Windows 7 Professional
  • Windows 7 Ultimate
  • Windows Server 2008 R2 Standard
  • Windows Server 2008 R2 Enterprise
  • Windows Server 2008 R2 Datacenter
Keywords: 
kbprb kbsurveynew kbexpertiseadvanced kbhotfixserver kbautohotfix kbqfe kbfix KB982383

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