Displaying Incorrect Video Card Memory Size

You might want to check your Windows Vista Video Card Memory Size to check if it reports correctly. On some occassions it doesn’t show your correct settings.

Symptoms as described by Microsoft:

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.

You can read and find the necessary download updates for this here.