Cayce
Level 1 (4 points)

Q: Asking Advice on Possible Bad Graphics Card (GPU)

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.

 

Cayce

 

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)

iMac, OS X Mountain Lion (10.8.5), 2011 27" iMac

Posted on Jan 24, 2015 4:47 PM

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Cayce

Q: Asking Advice on Possible Bad Graphics Card (GPU)

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  • by Muufungman,

    Muufungman Muufungman Jan 24, 2015 7:04 PM in response to Cayce
    Level 2 (185 points)
    Jan 24, 2015 7:04 PM in response to Cayce

    Sounds an awfully lot like a GPU failure, just curious but does it display the same symptoms in Safe Mode?

    Your iMac is actually a 2010 model and eligible for the recall unfortuately.

     

    Fixing the problem:

     

    I have heard reports of people with issues similar to you, to solve it they baked the Graphics Card in the oven for a few minutes.

    As Apple are not willing to replace your GPU and you are then by all means replace it, read on below ->

     

    This is one of the most expensive upgrades for macs, it is done by few and it is more likely to be a flop than a success.

    Others here suggest that the card is soldered to the board, but it is not, just take a look at the fixit teardown.

     

    1: You will need someone to install it

    You can install it yourself if you are confident enough, instructions - https://www.ifixit.com/Guide/iMac+Intel+27-Inch+EMC+2309+or+2374+Graphics+Card+R eplacement/9553

     

    2: You will need a compatible graphics card (any card that supports UEFI and is MXM B size)

    The best candidate for this upgrade is a card out of a iMac of the same gen (2010-2011), a card such an AMD 5670M, 6750M, 6770M, 6970M are great upgrades and best suited for your iMac, I am pretty sure that the card will need to be an MXM-B size chip to fit properly

     

    The only way to get a card that will be 100% compatible will be if you get it from an existing system.

    Also a better card may shorten the life of your iMac as the existing cooling system isn't built for bigger cards.

     

    3: Where to get the card?

    Not many places will stock cards of this age or rarity, I suggest start looking at places like eBay, I saw this card - http://www.ebay.com/itm/NEW-661-5967-Video-Card-AMD-Radeon-HD-6770M-512MB-for-iM ac-27-Mid-2011-A1312-/181146081545

    They sell a variety of Graphics Cards, and have pretty good feedback.

    Have a shop around and choose carefully.

     

    These are suggestions, I am not held responsible for any damage that you do to your iMac

     

    Hope this helps and Good Luck!