this is 99% windows issue. The real problem is that you have to run max as administrator for some reasons which should be fixable by autodesk, if it really helps...
Yes, that's true. I've tried to contact Autodesk when I've noticed this issue with Autocad in 2015, but they didn't do anything to fix it.
Now I can see that Max 2016's and 2019's viewport performance is lower if it's run not as admin. Maybe it's because of some settings on my computers, IDK...
Could you guys write here if you have the same situation on your workstations?