This issue is usually occurs when your computer has an Intel onboard graphics and prefers that over the discrete graphics card like an NVIDIA or AMD.
Windows 10 (April 2018):
Follow the instructions in this tutorial to set the high performance graphics settings on Windows.
From this menu you can manually add applications to High Performance mode so they will use the Radeon GPU.
AMD:
Radeon Settings > Preferences > Additional Settings > CCC Slim > Power > Switchable Graphics Application Settings.
From this menu you can manually add applications to High Performance mode so they will use the Radeon GPU.
NVIDIA:
NVIDIA Control Panel > 3D Settings > Manage 3D Settings -> Program Settings > Select a Program to Customize > (Maybe uncheck Show only programs found on this computer) > Select Preferred Graphics Processor.
Set your graphics processor to High Performance NVIDIA Processor.