Application developers can direct the NVIDIA Optimus driver at runtime to use the High Performance Graphics to render any application – even those applications for which there is no existing application profile.
This can be achieved by exporting a global variable named NvOptimusEnablement.
The Optimus driver looks for the existence and value of the export. Only the LSB of the DWORD matters at this time. A value of 0x00000001 indicates that rendering should be performed using High Performance Graphics. A value of 0x00000000 indicates that this method should be ignored, and the default graphics card will be selected.
This is an example method to enable this feature:
extern "C" {
_declspec(dllexport) DWORD NvOptimusEnablement = 0x00000001;
}
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For further information, refer to the Nvidia Optimus Documentation, specifically the section Global Variable NvOptimusEnablement.