Vertical Sync: Check your FPS in the game

[Drum-Sem]

I suddenly discovered that when vertical synchronization was enabled, the game was running at 30 fps.
Turn off and set the fps lock in the nvidia control panel (if you play 60 fps just like me).

[C̪͙͉a̡̼s̞͉t͕̘̝o̺̟̝r]

For me the vsync seems to lock at 30fps, too although everything is set at 60fps. Funnily in the main menu i get 60fps straight. Ingame when i hit Esc for the menu the fps also suddenly climb to stable 60fps. when i leave the menu and go back to the game it drops to 30fps again.
fps lock in NCP indeed helps, but i'm curious to why it behaves like this.