So you can get more refined steps of framerates when vsync is on?
With double buffering and vsync if your fps drops below 60 on a 60 Hz refresh rate you will go down heavily to 30, then 20, 15, 12, 10, and so on.
http://www.hardforum.com/showthread.php?t=928593There is an option for enabling triple buffering in most graphics card control panels, I believe, but it means one has to go to the GPU control panel whenever he wants to switch vsync off/on, or suffer the performance loss of triple buffering without vsync.
I'm not sure how easy it would be to implement in a library, though I have already seen games with it, although DX, but it would mean you could switch triple buffering on and off together with vsync.