I tested the new Nvidia Adaptive Sync inside the advertised Freesync Range (55-75Hz) today. Adaptive Sync seems to work fine, but Frameskipping on 75Hz-mode is still a problem. I solved this issue by setting the Monitor refreshrate in the windows settings manually back to 60 Hz and afterwards to 75Hz. Sadly I have to do this steps again everytime i restart Windows because it seems to frameskip again after windows restart.
All tests were done with UFO-Frameskipping test and Nvidia pendulum demo.
Edit: Also no problem with Rainbow 6 Siege