As above, ive been trying to figure out how to solve screen tearing on my rMBP and here are my findings. My setup - base rMBP, Mountain Lion, fresh install with only gfxcardstatus and VLC. How i trigger screen tearing - 1.) Set gfxcardstatus to auto launch upon login and keep rebooting till problem comes up 2.)switch around gfxcardstatus graphic modes as well as Apple's graphic switching settings until growl notifications of graphic mode switch stop appearing, afterwhich i log out and log back in to find major tearing. 3.) Screen tearing is just something waiting to happen with gfxcardstatus turned on, the signs stated below show it would most definitely happen after logging out and logging back in, so it may happen naturally without intentional triggering Signs that screen tearing is about to happen - slow login, slow logout, weird positioning of password field at login page, gfxcardstatus refusing to acknowledge graphic mode switch (no notifications appearing stating success of switch), vlc refusing to open, disappearing text in text fields like youtube search bar, page tearing on google results. Remedies - only way to get rid of the screen tearing when it happens is a reboot Solution so far - do not use gfxcardstatus (bummer) , I am also not 100% sure avoiding gfxcardstatus will solve it, but so far i haven't encountered screen tearing with gfxcardstatus off. Am starting to wonder if the hd4000 is the culprit as it is also causing other problems for the entire new line of macs like crashing etc. Help and input appreciated, thanks!