VSYNC 1 frame and 2 frames?

[smexyghost]

In Far Cry I have the option VSYNC: OFF. 1 FRAME, 2 FRAMES.
When its OFF there is tearing, so then I put it on 2 frames and got only 30 fps (and only 30 fps) but when I put it on 1 frame, it got 45-55 fps.
What is the difference?

 

[ccampy]

Vsync 2 or every second frame so it will run at half refresh rate 1 is every frame so will run at near fully refresh

 

[smexyghost]

Vsync 2 or every second frame so it will run at half refresh rate 1 is every frame so will run at near fully refresh

well 1 frame doesn't go near my refresh rate (144) but with OFF it has a higher fps, so does VSYNC take a few fps away?