27" iMac video artifacts.

Discussion in 'iMac' started by Chabba, Jul 21, 2014.

  1. Chabba macrumors regular

    Jul 17, 2011
    Late 2012 27" iMac i7 w/ GTX680MX 2GB, 1TB Fusion drive. OS X 10.9.4

    I've noticed similar type artifacts for a few months now.
    It usually appears along the top like the video below.

    It isn't the monitor because I was able to record it with Quicktime, so it comes from the video card.

    I suspect a faulty video card.
    Other issues have included many dropped frames playing back online 1080p video.
    Processing effects w/ Final Cut Pro has caused FCP X to crash a few times.
    Civ 5 will not playback anything after the game is finished (regardless how long the game was). That issue goes back to when I was running OS X 10.8 and have reformatted/reinstalled OS X (10.9) and no change.

    Are there any good tools to help diagnose a bad video card w/ Mac? I'm only familiar with Windows when it comes to troubleshooting these kinds of issues.

  2. scaredpoet macrumors 604


    Apr 6, 2007
    Do you have AppleCare on that iMac? Hopefully you do, as you'll probably need it. Given the issues you describe, that definitely looks like a bad GPU.

    You may want to give Apple Hardware Test/Diagnostics a try to see if the tests come up with anything. There are more thorough diagnostics that target the graphics card specifically, but they are generally only run by Apple technicians using software they have available in-shop at the apple store, or in their repair depots.

    If the built-in tests don't reveal any problems, your next step would be to to back up your data, then wipe the drive and do a fresh OS install, since that's exactly what Apple tech support will tell you to do (or will do themselves when the iMac is in their hands). My guess is it's unlikely that will change anything, but if you can rule it out before they ask, then that helps speed things along.

    Obviously, if you still get the glitches post-reinstall, then it's definitely the hardware.
  3. Chabba thread starter macrumors regular

    Jul 17, 2011
    Yeah, I have Apple Care.

    That's what I was looking for, more tests. I'll run the self-diagnostics and go from there. Thank you.

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