Maximum pre-rendered frames desyncs the game - why?

When I change MPRF too low or too high, the maximum pre-rendered frames option in nvidia panels, my game desyncs and I get horrible hitreg and players become insanely good. Why?

The default option 3 / use application setting is desynced too. I need to use 6 (set with nvidia inspector) for the game to be playable. Why is this happening?

Edit: With MPRF 1 2 3 (default) 4 and 8 9 10, the game is completely unplayable. You can try the extremes yourself in nvidia inspector. 1 is the lowest. "0xFFFFFFFF" is the highest. In all other games, if you set MPRF to 0xFFFFFFFF, you get a very high input lag. In CSGO you get zero input penalty?? Must be related to this somehow?

I'll make a video and create a new post later to demonstrate this.