| The vwait parameter defines whether or not the graphics card will wait for the vertical blank before flipping the screen. The vertical blank is an event that occurs at the frequency of the monitors refresh rate, and corresponds to the point in time when the last line on the screen has been drawn, and the top line is about to be drawn by the monitor. By waiting until the vertical blank, you ensure smooth updates to the screen as the image being drawn by the monitor will change only once the entire screen has been drawn by the monitor, and the screen is just about to start being refreshed.
However, it is worth noting that this setting applies to the graphics card only, and some graphics cards allow the user to disable the vertical blank event. Therefore, if you rely on Flip alone, the display may be corrupted on certain setups. The VWait command may be useful to you in this respect, as it forces the CPU to wait for the vertical blank (as opposed to the graphics card), and this cannot be disabled. Hence true silky smooth updates are best achieved using "VWait : Flip False".
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