I am getting the following error when I set the target device as GPU:
NetTrain::trgdevegpu: TargetDevice -> GPU could not be used; a supported NVIDIA GPU was not found. If you are using an external GPU, ensure it is attached and recognized by your OS; restarting your system may help. Additionally, check that you are using the latest drivers from http://www.nvidia.com/Download/index.aspx.
Does Mathematica 12 support GT 730 CUDA?