Windows Game bar and Nvidia Adaptive v-sync relation

[vidha]

I noticed by accident that when Windows 10 (build 1709) Game bar was enabled, the Nvidia Control Panel setting "Adabtive vsync 1/2 refresh" seemed to work on my 60HZ monitor. It seemed to work the same way as normal Vsync capped at 60HZ, only that it now capped at 30HZ. 

This gave a really smooth and almost stutterfree experience (more than just using the internal limiter in P3D). I must add that it seemed to work best with unlimited FPS and triple buffering and vsync still enabled in P3D.

When I turned Game bar off again, the setting in Nvidia Control Panel  "Adabtive vsync 1/2 refresh" didnt have effect again, and FPS was back at capped 60HZ

I wonder why this is the case, and what causes this. Is this something related to WDDM in relation to the Nvidia drivers? I always heard this setting work for some, and not for others. This may be the cause as some disable Game bar and others do not.

Anyway, it was interesting to be able to takeoff from Aerosoft EGLL at heavy clouds in PMDG QOTSII with no stuttering at 30HZ. Of course capped at VSYNC 60HZ is better, but this is a tradeoff. My PC hardware is quite old 2600K with GTX 980.