How to force Photoshop to use the Nvidia GeForce GTX Titan ?

Hi

I'm using the latest version of Photoshop.

I use my onboard-graphiccard as a standard display.

I have an additional Nvidia GeForce GTX Titan on my board which I use for GPU-Rendering in 3D-Softwares.

When I start Photoshop under Preferences, I see only my onboard graphiccard - no GPU acceleration.

I tried to set it in the Nvidia Control Panel (under 3D Preferences) see here:

But nothing happens, I still have only the onboard card to choose.

How can I force Photoshop to use the Nvidia GeForce GTX Titan ?

Kind regards

Alain