An interesting quirk I was unaware of, Microsoft has publicly acknowledged an error in the DirectX API that in certain situations (Having over 1GB of Video Memory and over 4GB of System Memory), the API to return total memory mail return erroneously small numbers. Like so:
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
NVidia has built a driver workaround to fix this for some of their cards, and provides a little application called NVTagToggle.
On Windows Vista and Windows 7, NVIDIA provides GPU driver support to work-around this issue for GPUs with less than 3GB of memory. The workaround forces the video memory to the maximum amount these DirectX APIs can report, sacrificing some of the total memory. This is called “Compatibility Mode”.The application “NvTagToggle.exe” linked below can help you detect this scenario and configure this workaround, as well as reset the GPU driver to its default behavior. The application is only supported on Windows Vista and Windows 7, for NVIDIA GPUs with less than 3GB of memory.
So if you’ve experienced this before, check it out and let us know your results in the comments.
via Direct-X diagnostics tool (DXDIAG) may report an unexpected value for the display adapters memory..
