2010 iMac freezes with green squares all over screen?

Discussion in 'iMac' started by qwimjim, Jun 24, 2013.

  1. qwimjim macrumors regular

    Joined:
    Jan 5, 2011
    #1
    my iMac started actiing up recently, and freezes 1-3 times a day now where all i can do is a hard reboot. it often happens when i'm opening a jpg, the screen will freeze and all these green squares will appear on the screen. i booted with the installation disc and did a hardware test, no problems found.. my hard drive had some issue but i also did a repair in disk utility.. but the freezing keeps happening. has anyone seen this before?

    https://www.dropbox.com/s/g92i7piahgaftd1/2013-06-24 15.30.19.jpg
     
  2. migliore macrumors newbie

    Joined:
    Jun 24, 2013
    #2
    Console?

    Have you checked the messages in console? My Early-2009 24" iMac has a similar problem where it looks like the video craps out and then the computer becomes unusable (have to reboot). My console looks like this right before "restart":
    4/22/13 6:37:14.000 PM kernel[0]: NVDA(OpenGL): Channel exception! exception type = 0x8 = Fifo: Watchdog Timeout Error
    4/22/13 6:37:23.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
    4/22/13 6:37:51.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
    4/22/13 6:38:23.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
    4/22/13 6:38:43.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
    4/22/13 6:39:15.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!

    I think it is a bad graphics card and will be over $500 to fix, a 4yo computer.
     
  3. qwimjim thread starter macrumors regular

    Joined:
    Jan 5, 2011
    #3
    where can i find this log after a crash?

    fortunately for me i bought this imac second hand and they had purchased an extended warranty with best buy that expires in december
     
  4. qwimjim thread starter macrumors regular

    Joined:
    Jan 5, 2011
    #4
    whoops just realized all you have to do is open console :) was confusing it with terminal. will paste a few lines next time it crashes
     
  5. qwimjim thread starter macrumors regular

    Joined:
    Jan 5, 2011
    #5
    ok just had a crash, this time i wasn't even using the computer, i left to do something, came back and screen was frozen.. could move mouse cursor around but clicking not working, nor trackpad clicking, nor keyboard.. and no green squares this time. i came back to the computer and rebooted at 11:14

    https://www.dropbox.com/s/7bfeqyadmqay9mo/console.jpg
     
  6. qwimjim thread starter macrumors regular

    Joined:
    Jan 5, 2011
  7. zuri macrumors member

    Joined:
    Mar 29, 2013
    #7
    Hello qwimjim

    It will be great if you can provide us with some system logs
    go to apple logo -> about this mac -> more info -> system report -> logs -> panic (system crashes) report

    in my opinion it is based on faulty GPU when entering into 3D mode or some graphical computing tast
    it happens a lot in hd6970m in 2011 27inch imacs for example

    you can also run unigine heaven or valley on your iMac and if you experience glithes and graphical artefacts or perhaps kernel panic you know it is based on GPU

    [​IMG]
     
  8. qwimjim thread starter macrumors regular

    Joined:
    Jan 5, 2011
    #8
    thanks! but unfortunately i don't have "panic (system crashes)" in my list of logs, is it because i'm running 10.6.8?

    am i to assume you didn't find anything in the console screen shots i posted?
     
  9. zuri macrumors member

    Joined:
    Mar 29, 2013
    #9
    I found nothing linked with error. Perhaps if you could filter console logs for openGL and for program which is making glitches it will be perfect.

    What about unigine valley? No errors ?
     

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