In some scenarios, games and benchmarks perform more poorly than expected on a Windows Vista-based computer. This issue occurs when the games and the benchmarks use multiple display adapters in a Linked Display Adapter (LDA) configuration.

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A graphics processing unit (GPU) or part of a GPU link may incur a small scheduling latency on a new Direct Memory Access (DMA) packet. This is true if the DMA packet is submitted to the GPU that has previously run out of work and if another GPU in the linked configuration is very busy. In some scenarios, significant starvation of one or more GPUs in the linked configuration reduces the expected performance of an application.

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Update information

To resolve this problem, install one of the following updates, as appropriate for your situation.

Update for Windows Vista

http://www.microsoft.com/downloads/details.aspx?FamilyId=4D611CBC-DDBB-4744-8437-76A470DCFB93 (http://www.microsoft.com/downloads/details.aspx?FamilyId=4D611CBC-DDBB-4744-8437-76A470DCFB93)

Update for Windows Vista for x64-based Systems

http://www.microsoft.com/downloads/details.aspx?FamilyId=C8C0D2EE-A087-4D82-8579-A0CB7C3E8A2B (http://www.microsoft.com/downloads/details.aspx?FamilyId=C8C0D2EE-A087-4D82-8579-A0CB7C3E8A2B)

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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

There are no prerequisites for installing this hotfix.

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 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 item in Control Panel.

Windows Vista, x86-based versions

File name	File version	File size	Date	Time	Platform
X86_5b7480f6146b3db42d4c09f17183becc_31bf3856ad364e35_6.0.6000.20721_none_f72d9fdff593db00.manifest	Not Applicable	696	15-Nov-2007	14:42	Not Applicable
X86_microsoft-windows-lddmcore_31bf3856ad364e35_6.0.6000.20721_none_aa575735ff93258e.manifest	Not Applicable	8,958	15-Nov-2007	14:42	Not Applicable
Cdd.dll	6.0.6000.20721	37,376	15-Nov-2007	04:16	x86
Dxgkrnl.sys	6.0.6000.20721	621,568	15-Nov-2007	02:09	x86

Windows Vista, 64-bit versions

File name	File version	File size	Date	Time	Platform
Amd64_c07c2d5e68c6e04043943f369559c1a2_31bf3856ad364e35_6.0.6000.20721_none_11c1f42f44d375d9.manifest	Not Applicable	700	15-Nov-2007	14:42	Not Applicable
Amd64_microsoft-windows-lddmcore_31bf3856ad364e35_6.0.6000.20721_none_0675f2b9b7f096c4.manifest	Not Applicable	9,223	15-Nov-2007	14:45	Not Applicable
Cdd.dll	6.0.6000.20721	47,104	15-Nov-2007	05:06	x64
Dxgkrnl.sys	6.0.6000.20721	879,104	15-Nov-2007	02:25	x64

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

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For more information about the multiple graphics card issue in Windows Vista, click the following article number to view the article in the Microsoft Knowledge Base:

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