For plotting and MATLAB graphics, you cannot currently choose which GPU is used from within MATLAB. MATLAB makes a call to the system through OpenGL and uses the device that the system provides. Generally this is the dedicated graphics card and not the integrated GPU if this is the setup you are describing. To see which one is being used, you can use the following command once MATLAB is installed:
>> opengl info
However, you can change the default graphics card in your system's Control Panel. Then MATLAB chooses that default graphics card. Here is a link which gives the steps to set the default graphics card in your system:
As far as performing GPU computations, MATLAB's Parallel Computing Toolbox currently supports NVIDIA GPUs that support CUDA 1.3 or later. To see the full list of supported GPUs, please click the following link:
When performing GPU computations, the device can be chosen by using the "gpuDevice" function.
