Traditionally TVs only support 60 Hz refresh rates  (or 50 Hz for older PAL sets), so you either render a new frame for each frame the TV can refresh, or you display a frame for two TV refreshes.<p>Thi sisn&#x27;t strictly true any more, since many TVs now support 72 Hz (to be able to display 24 fps content like film), but my guess is that doesn&#x27;t have wide enough support to rely on.