Since upgrading to Windows 1909 I have had issues with my dGPU not working in Vectorworks. This has happened to two different laptops and in both instances the Nvidia dGPU would not turn on, and the on board GPU was doing all of the work.
I reinstalled the Driver, and used the Nvidia control panel to set the High Performance Graphic card to be used always. It still wouldn't work.
I then found this article: https://pureinfotech.com/set-gpu-app-windows-10/
Windows has changed how you set which GPU to use in which app, and it never seems to turn on dGPU unless you force it.
Thought that I would share just in case any of you hit the same issue.
The method on https://pureinfotech.com/set-gpu-app-windows-10/ Fixes the issue.