VSync not working properly in fullscreen?

When I play my game in full screen at full resolution with the default fantastic settings set. My frame rate is like 345 fps even though vsync is on. However my player movements and such feels like its studdering. However when I play the game in windowed mode at the same resolution my game is locked at 60fps and I dont seem to find any studdering everything felt buttery smooth. Is this a glitch in unity? or is there something in my settings not configured properly?