You have a system with 1GB or greater of Video memory, and 4GB or greater of system memory (RAM).
You run the Direct-X Diagnostics tool, and it reports that you have an unexpectedly low amount of Approximate Total Memory on the display tab.
You may also see issues with some games or applications not allowing you to select the highest detail settings.
The API that DXDiag uses to approximate the system memory was not designed to handle systems in this configuration
Microsoft is working to resolve this in future releases
On a system with 1GB of video memory, the following values are returned with the associated system memory:
System Memory Reported Approximate Total Memory 4GB 3496MB 6GB 454MB 8GB 1259MB