Windows Vista displays the incorrect dedicated video memory size for certain display adapters

Windows Vista displays the incorrect dedicated video memory size for certain display adapters. The incorrect dedicated video memory size appears in the system display settings and in the Windows System Assessment tool (Winsat.exe).

This problem occurs if the dedicated video memory size is not a power of 2. For example, if a display adapter has 320 megabytes (MB) of dedicated video memory, Windows Vista shows that only 256 MB of dedicated video memory is available for the display adapter.
This problem occurs because Windows Vista uses an incorrect rounding algorithm to calculate video memory size.

Service pack information

To resolve this problem, obtain the latest service pack for Windows Vista. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
935791 How to obtain the latest Windows Vista service pack

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.


No prerequisites are required.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

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 nameFile versionFile sizeDateTimePlatform
Package_1_for_kb938838~31bf3856ad364e35~x86~~ applicable1,77508-Sep-200715:20Not applicable
Package_2_for_kb938838~31bf3856ad364e35~x86~~ applicable1,78608-Sep-200715:20Not applicable
Update.mumNot applicable1,90108-Sep-200715:20Not applicable
X86_3fd6c00c54e3177499f028128e7432ff_31bf3856ad364e35_6.0.6000.20676_none_1ab86fa2f803c141.manifestNot applicable69508-Sep-200715:20Not applicable
X86_bd6aa29ed63dc229fe53c9f3d1e9fd85_31bf3856ad364e35_6.0.6000.20676_none_650c0cc4df4a3239.manifestNot applicable70108-Sep-200715:20Not applicable
X86_microsoft-windows-perfcentercpl_31bf3856ad364e35_6.0.6000.20676_none_62cad3b6105fa076.manifestNot applicable17,01108-Sep-200715:20Not applicable
X86_microsoft-windows-themeui_31bf3856ad364e35_6.0.6000.20676_none_835c44fa37ab968e.manifestNot applicable42,80808-Sep-200715:20Not applicable
Windows Vista, 64-bit versions
File nameFile versionFile sizeDateTimePlatform
Amd64_385561d8c1395012ea0a093b473a7745_31bf3856ad364e35_6.0.6000.20676_none_588d4f6740c360e1.manifestNot applicable1,05008-Sep-200715:20Not applicable
Amd64_660e4cf69088c8a8f9002bf9a7bd5c0a_31bf3856ad364e35_6.0.6000.20676_none_6be7ede63c8b6ec2.manifestNot applicable1,03808-Sep-200715:20Not applicable
Amd64_microsoft-windows-perfcentercpl_31bf3856ad364e35_6.0.6000.20676_none_bee96f39c8bd11ac.manifestNot applicable17,04908-Sep-200715:25Not applicable
Amd64_microsoft-windows-themeui_31bf3856ad364e35_6.0.6000.20676_none_df7ae07df00907c4.manifestNot applicable42,86408-Sep-200715:25Not applicable
Package_1_for_kb938838~31bf3856ad364e35~amd64~~ applicable2,00408-Sep-200715:20Not applicable
Package_2_for_kb938838~31bf3856ad364e35~amd64~~ applicable2,00908-Sep-200715:20Not applicable
Update.mumNot applicable1,91308-Sep-200715:20Not applicable
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 Vista Service Pack 1.

Checking the video memory size of the display adapter

To check the video memory of the display adapter, follow these steps:
  1. Open the Personalization item in Control Panel. To do this, click Startthe Start button, type Personalization in the Start Search box, and then click Personalization in the Programs list.
  2. Click Display Settings.
  3. Click Advanced Settings.
  4. On the Adapter tab, the Dedicated Video Memory item displays the video memory size of the display adapter.
Or, you can use the Windows System Assessment tool to check the video memory of the display adapter. To do this, follow these steps:
  1. Click Startthe Start button, type cmd in the Start Search box, right-click cmd.exe in the Programs list, and then click Run as administrator.
  2. At the command prompt, type the following command, and then press ENTER:
    winsat.exe /v
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

Article ID: 938838 - Last Review: 10/08/2011 16:35:00 - Revision: 4.0

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

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