Okay, since some of you do not seem to understand what V-Sync is, back to basics.
First.
Every rendering engine uses a two sided coin frame buffer, sides which are called front buffer and back buffer. The front buffer is a memory zone containing the picture currently displayed. The back buffer is a memory zone containing the next picture to display, i.e. the picture currently drawn by the 3D engine. The reason for this is obvious, when drawing the next picture (that is, during the 16.67ms at 60fps), the resulting picture is an utter mess of "work in progress". So there is a need to store the previous picture to display it.
As you may guess, there is a need to swap the front buffer and the back buffer when drawing is done to display the next picture. The front buffer becomes the back buffer, and vice versa.
Second.
On any display, the refresh rate, i.e. the scan of the front buffer, is done at fixed intervals (every 16.67ms when set at 60fps).
So.
V-Syncing merely means that the swap between the front buffer and the back buffer are synchronized with the display refresh rate so that it happens when the display scan of the front buffer is just between the last line of refresh n-1 and the first line of the refresh n.
This is done because when swapping occurs during the display refresh, "half" of the screen display picture n-1, and "half" of the screen displays picture n, thus resulting in what is usually called "screen tearing".
For reasons I will not detail here, screen tearing tend to be very visible when it occurs, especially with fast moving pictures, but is also very random, so may or may not be noticeable depending of the situation.
Of course, V-syncing means that if your 3D engine cannot draw frames in less than 16.67ms, then it cannot swap buffers as expected, so it must wait for the next refresh to begin working on the back buffer again, thus resulting in HALVING the fps (so, down to 30fps).
Triple buffering is merely adding a third working buffer in order to increase effective fps while maintaining V-Sync, but has some nasty side effects that I will not explain here (slight input lag is usually one of them).
The reason why most modern rendering engines use a "dynamic V-Sync" (basically, a V-Sync that deactivates when a frame is rendered in more than 16.67ms and reactivates when a frame is rendered in less than 16.67ms) is obvious. When capable of running at 60fps, there is no screen tearing. When unable to run at 60fps, there is almost no frame-rate drop, at the expense of screen tearing.
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Hope I made myself clear enough so that most of you may understand what's going on when speaking of V-Sync and frame-rates.
Well, back on topic, screen tearing has nothing to do with displays, it is mostly due to the rendering engine implementation, and in GT5 case, to the inability to maintain 60fps consistently.
