How can I stop Matlab from using dedicated GPU in laptop?

I can't stop Matlab from using my dGPU even after I've set Nvidia's program to use "Integrated Graphics". I was thinking that Matlab enables the Nvidia chip anyway, because it has CUDA support?

Setup: Matlab 2015a, Win7 x64, Intel HD4600 + Nvidia GTX970M

Regards Martin

[Walter Roberson]

Are you using any of the gpu functions such as gpuArray() ? Those can only be executed on the NVIDIA; there is no GPU support for any other manufacturer.

Answer 1

[TJ Smith]

You can turn off the GPU with this code:

gpuDevice([]);

I found this on this page: https://www.mathworks.com/help/distcomp/gpudevice.html which described it as:

gpuDevice([]), with an empty argument (as opposed to no argument), deselects the GPU device and clears its memory of gpuArray and CUDAKernel variables. This leaves no GPU device selected as the current device.

Answer 2

[Adam]

doc gpuDevice

You should be able to get a list of GPU devices with

g = gpuDevice;

Then select a particular device from that list by its index:

D = gpuDevice(idx)

[Martin Jensen]

This only lists the CUDA devices and my Intel chip does not support CUDA, hence I can only select the Nvidia card. Shouldn't there be a way to deselect this functionality completely? Okay doc says: gpuDevice([ ]), with an empty argument (as opposed to no argument), deselects the GPU device I will try setting it in the startup.m

[Edric Ellis]

I'm not quite sure why you'd want to do that though - MATLAB doesn't automatically perform any numeric computations on the GPU, it only uses it if you explicitly put data there using gpuArray...

[Ryan]

The reason one might want to do that—because the user mentioned laptop—may be that this person is looking for a way for matlab not to mark itself as potentially using the GPU for the mac os operating system. On laptops, that can automatically switch on high performance computing mode, which turns on more energy expensive GPU chip. It's power saving to have high perf mode off.

[Yetti]

Also, on a microsoft Surface Book, the dGPU is in the keyboard base. Detaching the screen requires quiting matlab when matlab grabs the dGPU automatically.

[Kenz Dale]

Frustratingly, this command is only available if you have the Parallel Computing Toolbox. So I can't detach my Surface Book 2's screen unless I quit Matlab. This is bonkers, as one of the primary reasons I moved from macOS to Windows was to leverage the awesome power of the Surface Book.