Is my graphics card screwed?

Discussion in 'iMac' started by -pete-, Feb 2, 2013.

  1. macrumors member

    Apr 20, 2011
    Hi all,

    So about a month ago I got my 2011 iMac back from repair where they apparently replaced the logic board, graphics card and LCD (which thankfully I didn't have to pay for!) due to it completely locking up and refusing to boot (details here).

    Everything has been fine for a month until a couple of days ago. The screen randomly started "glitching" with lines going across it, then it would appear offset (wrapping half way around the screen) or with scan lines going through it then it would go into a "seizure mode" (my friends name for it not mine!) where it would flash brightly between bight white and grey before crashing to a black screen.

    The issue originally appeared in windows 7 so I booted into OSX which seemed fine and stable for a couple of days until last night when a similar thing happened.

    I left it switched off for the night and returned this morning to find that it won't boot into any OS at all and I have pink lines going vertically down the screen for the start of the boot process until it locks up entirely, see the photos below:



    Is my graphics card hosed?
  2. macrumors 65816


    Aug 29, 2009
    Whatever the problem is, whoever 'fixed' it apparently didn't fix it. So I'd go back to them and explain what's happening, since it's obviously not working right.
  3. macrumors newbie

    Mar 9, 2013
    Hey -pete- ,
    did you manage to find a solution for your problem? This problem occurred for me first about a week and a half ago. At first it looked exactly like yours and it would still boot up. I tried some suggestionsI found in different forums but at this point it doesn't even boot anymore - it just stays on the grey screen.

    So, I'd be very thankful for any followup on your issue and to hear if - and if so, how - it was resolved.

  4. macrumors 68040

    Oct 21, 2012
    If it stays on the grey screen it's likely going to be your graphics card.

    The issue above could be any of graphics card, lvds cable or the LCD itself. I would verge on it being the graphics card though. Op: take it back to Apple and have them put a new graphics card in.
  5. macrumors 68000


    Aug 18, 2008
    At the bend in the river

    I would like to see an update on this as well, as my uncle's iMac (20 is having very similar issues. So just now here I am in safari and it started acting up. Safari window went black, all the tabs looking like a cable TV channel that you didn't pay for, and I could quit photoshop, but not safari. Then I scaled the safari window and now everything is back to normal. for now... On startup, the first time, on which it ultimately did not start up, the display demonstrated the striations like in the OP's post, only not as defined. but it didn't start up, and we had to reboot. Anyway, if you find out anything out I'd love to hear.
  6. macrumors 68040

    cocky jeremy

    Jul 12, 2008
    Huntington, WV
    General rule: If something is happening to make you think your graphics card is bad, it usually is.. unless it's a bad logic board.
  7. macrumors newbie

    Sep 13, 2009
    Any Update?

    A friend is having the same problem and is out of warranty. We are afraid how much this is going to cost her...was it the graphics card? That's my guess even though everyone says our hardware code is the HDD or HDD Fan....

    anything you found would be a great help. thanks!
  8. macrumors member

    Mar 29, 2013

    99% of this symptoms I repaired was caused by graphics card.
    Try to run a "valley" test on it, that loads your graphics a lot and if its faulty you will see many image defects on screen.

    Cinebench is quite good to compute image defects too.
  9. macrumors regular

    Jul 21, 2010
    The product page states that it requires "Mac OS X 10.8+ (Mountain Lion)". Shame, as I've had a few weird glitches recently on my 2010 27". Is the Apple Hardware Test likely to pick up transient GPU-related issues?
  10. macrumors member

    Mar 29, 2013

    sorry for my recent inactivity...
    If you run ASD version of apple tests you can also check GPU tests. But as I experienced, this set of tests will give you fail status only if your GPU is almost totally broken and cant render basic vertex operations.

    If you want I can upload whole ASD set of test for your machine and you can give it a try.
  11. macrumors regular

    Jul 21, 2010

    I'm not quite sure what you mean by the "ASD version of apple tests". When I ran the tests off the Snow Leopard CD, all it found was something relating to the hard drive fan motor.

    But, I took a photo of the screen when it crashed, and that was enough to justify the replacement of the graphics card at the same time as my hard drive was swapped out (the iMac drive recall). Neat.


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