Are you running the latest update of SU2016 ? (16.1.1449)
Have you verified that Nvidia Control Panel is set to run sketchup.exe using your Quadro GPU ?
Are you using a “fast style” for your modeling scene ?
Does your modeling scene have performance hogs like shadows and textures switched off ?
… and have you read and applied these techniques …
* A “modeling scene” is a scene page specifically set up for fast modeling and not for display, output, rendering or LayOut viewports. Mine is named “Work” in my template.
Lastly, have you compared against SketchUp 2018 running in trial with the Windows 10 slow selection patch applied ?