Some of you may have noticed that the rMBP audio stutters a lot when playing music or videos (like watching youtube especially). Apparently this is due to automatic graphics switching. If you turn it off (aka using discrete graphics all the time), the problem goes away. This also helps some of the jerky scrolling issues in Safari. It doesn't totally eliminate it, but the performance is a lot better and much less laggy (as you might expect). To sum it up: switching causes stutter. Staying in integrated graphics only mode using gfxCardStatus also causes stutter, although seemingly less frequent, but might be the same issue. Staying in discrete only mode is perfect for audio and makes safari perform better, but draws more power and creates more heat. Obviously, gfxCardStatus is a good utility for managing this. But Apple should fix whatever in their drivers for the Intel gfx is causing this. Stuttering audio is unacceptable in any mode.