16.6ms is the maximum lag between the monitor receiving the framebuffer and drawing it - the average would therefore be half of that, and the minimum would be e

16.6ms is the maximum lag between the monitor receiving the framebuffer and drawing it - the average would therefore be half of that, and the minimum would be essentially zero. But, that's ignoring all the other little delays in the system. For instance, monitors have a delay of a few milliseconds. In short, this is a massive oversimplification.