Microsoft KB Archive/945149

= Graphics performance can be improved in certain multiple-GPU scenarios on a Windows Vista-based computer =

Article ID: 945149

Article Last Modified on 12/3/2007

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APPLIES TO


 * Windows Vista Business
 * Windows Vista Enterprise
 * Windows Vista Home Basic
 * Windows Vista Home Premium
 * Windows Vista Starter
 * Windows Vista Ultimate
 * Windows Vista Business 64-bit Edition
 * Windows Vista Enterprise 64-bit Edition
 * Windows Vista Home Basic 64-bit Edition
 * Windows Vista Home Premium 64-bit Edition
 * Windows Vista Ultimate 64-bit Edition

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SYMPTOMS
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.



CAUSE
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.



Hotfix Information
A supported hotfix is now 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 service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or 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. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

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, 64-bit versions


STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
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:

936710 When a DirectX 10 application runs on a Windows Vista-based computer that has multiple graphics cards, the computer does not use the secondary graphics card

Additional query words: SLI Scalable Link Interface

Keywords: kbqfe kbexpertisebeginner kbhotfixserver KB945149

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