Asking Advice on Possible Bad Graphics Card (GPU)

Discussion in 'iMac' started by dcayce, Jan 24, 2015.

  1. dcayce macrumors newbie

    May 9, 2009
    I've been dealing with some large scale issues on my 27" iMac and I'm looking for feedback on whether I'm on the right track for a solution. It began last year, and I had the problem resolved for a while after taking it to an Apple Store while it was still under the 3 year Apple Care coverage. That has since expired. The problems are now back, worse than before, to the point that I can barely keep the system going long enough to post this. The symptoms have been:
    • Thousands of small, multi-colored, pixellated squares scattered across my monitor, randomly appearing.
    • These squares are often blinking as large groups, while other areas of the squares will remain static.
    • Vertical and horizontal lines, sometimes broad, other times only a pixel or two in width.
    • Large irregular geometric shaped areas of solid black, white or color, sometimes static, other times blinking.
    • Occasionally on restart my desktop icons and icon bar will render as solid gray areas, forcing another restart.
    • Frequent screen lock-ups, especially when doing anything requiring the screen to redraw. This happens most in Logic, where the playhead is moving and the graphic of the sound wave is being rendered. Just a complete freeze, then either a blank white screen with an auto restart, or I have to do a forced shutdown, then restart.
    It's happening so much now, I can't do anything more resource intensive than type this in TextEdit, hoping I can launch my browser and post it on some forums.

    Mine is a 2011 series iMac, 27", and I know there was a problem with the GPUs during that time, where Apple did a recall and offered free GPU replacements. My serial number is outside the range for those qualifying for the replacement program, but I'm nearly 100% sure my GPU is the problem.

    What I'd like is a few opinions, based on the symptoms outlined here, on whether my diagnosis right, and what a good GPU replacement would be. I went into mine today, pulled the GPU and re-seated it, blew out a lot of dust accumulation, hoping these things would help, but they didn't. So I've been in there, and know the process. I just need advice on those two things.

    Thanks for any and all help.


    Processor 2.93 GHz Intel Core i7
    Memory 8 GB 1333 MHz DDR3
    Graphics ATI Radeon HD 5750 1024 MB
    Software OS X 10.8.5 (12F45)
  2. Dopeyman macrumors 6502a

    Sep 5, 2005
    Los Angeles!
    I believe you have a 2010 iMac, not a 2011 iMac... Apple's program is only for 2011 iMacs...

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