That's a great link, I had not seen that article before.  Though, in practice,the actual framerate to vary from the specified by much more than the -10 / +5 fps that he lists.<p>His final sentences might be relevant to this topic:<p><i>On high CPU load we might actually cut [the max framerate] into half, e.g. 30 frames/sec. OS X already does this in certain conditions.</i><p>Wish he had expanded on that a little more. Any idea what conditions cause OS X to halve the framerate?