If your program displays animated content, because it is a game or other multimedia-based application, your code should avoid updating your window content faster than the screen refresh rate. Drawing content to your local window buffer and flushing that content to the screen at more than 30 frames per second is usually a waste of CPU time. Most users cannot perceive updates at rates greater than 30 frames per second, so flushing more frequently is rarely needed. Changes introduced in Mac OS X v10.4 to eliminate visual "tearing" and other display artifacts are also likely to cause performance problems in code that flushes too frequently. . . . To avoid performance problems, you should never draw or flush your window buffers faster than the screen refresh rate. If you typically draw your content and then immediately flush it to the screen, you can use timers to notify your code when it is time to draw. Simply set a timer to fire at the same frequency as the screen refresh rate and have it call your drawing routine.