The dedicated graphics memory that is reported by the "Performance Information and Tools" item in Control Panel may be less than the actual graphics memory that is available for the primary video card in Window Vista

In Windows Vista, the dedicated graphics memory that is reported by the "Performance Information and Tools" item in Control Panel may be less than the actual graphics memory that is available for the primary video card.

The dedicated graphics memory is reported under Graphics in the "View and print details" page of the "Performance Information and Tools" item in Control Panel.

This problem occurs if the dedicated graphics memory on the video card is outside the scope of the algorithm that Windows Vista uses to calculate dedicated graphics memory.

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

Dedicated graphics memory is memory that is available exclusively for the graphics subsystem. Non-graphics applications and other subsystems cannot access this kind of memory.

Sometimes, the graphics driver or the graphics processing unit (GPU) on the video card reserves part of dedicated graphics memory. This memory is not available for general graphics processing. Therefore, this memory is not reported to the operating system as dedicated graphics memory. The "View and print details" page of the "Performance Information and Tools" item in Control Panel compensates for this behavior. This compensation helps match the dedicated graphics memory that is reported with the actual graphics memory that the manufacturer installed.

After the release of Windows Vista, some manufacturers released video cards whose dedicated graphics memory is outside the scope of the algorithm that Windows Vista uses to calculate dedicated graphics memory. For example, when a video card has 320 megabytes (MB) of dedicated graphics memory, the "View and print details" page may report only 256 MB of dedicated graphics memory.

For more information about graphics memory reporting and the Windows Device Driver Model (WDDM) in Windows Vista, see the "Graphics Memory Reporting through WDDM" white paper. To view the white paper, visit the following Microsoft Web site: