After some discussion with Maxon, I stumbled across an interesting discovery. If you press Shift + C and type "calculate fps" and run the test, the viewport becomes perfectly smooth in all versions past R20. Sadly, as soon as you stop the test it goes back to the same choppy viewport as before.
I'm trying to reverse engineer the process that goes on during the fps test to see what triggers it to become smooth. All help is appreciated on this. Also, Maxon suggested that maybe the issue lies within the windows system timer. You can download it here and try to set the timer to <=1ms and see if that helps. Didn't help in my case but still worth a shot.
