Came across this today, searching for a solution with my GTX 1050 Ti (Nvidia Optimus setup, i.e. graphics getting piped through the IGP).
I really hope, you're not right about fastsync replacing Adaptive vsync; Adaptive VSync has the advantage of reducing power consuption, which helps with cooling; "Fast-Sync", as described here, wouldn't provide that advantage.
*edit (2018-12-24)* Never mind... The latter part can be achieved independently by limiting the frame rate with tools like "NVidia Profile Inspector". Though I fear, it may saboage anti-tearing technologies, so adaptive vsync would still be the preferable solution.
