rubenlx

Q: OSX Lion + 2011 iMac 27'' + Video = Freeze

Hello.

 

Got a brand new 27'' iMac, installed Lion. The machine freezes randomly when starting to play videos, either on Youtube, Quicktime, iTunes.

 

When it freezes, the mouse still works, but the machine doesn't respond to any command, requiring me to hit the power button and restart the computer.

 

Searched on kernel.log and system.log, and found no crash/error/message.

 

Anyone suffering from the same problem? The machine is pretty solid, been running some OpenCL kernels too and they are ok. It's only video decoding (possible on the GPU) that seems to freeze randomly.

iMac, Mac OS X (10.7)

Posted on Jul 21, 2011 6:46 AM

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Q: OSX Lion + 2011 iMac 27'' + Video = Freeze

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  • by Johann P,

    Johann P Johann P Mar 2, 2014 5:18 PM in response to A. Richards
    Level 1 (0 points)
    Mar 2, 2014 5:18 PM in response to A. Richards

    Well, I'm happy to report that it's been more than a year since I had my ATI card changed and have not put it on sleep mode since then... AND I've had no problems eversince. I just use a screensaver that's completely black and dim down the screen using an app called Brightness Control and everything's perfect.

     

    Don't you all waste your time doing all these installs and uninstalls and tweaking the GPU speeds and voltage and fans here and there... we've done it all in this thread and it all comes down to one path... you need to replace your GPU eventually!

  • by cimbalino,

    cimbalino cimbalino Apr 3, 2014 7:32 AM in response to Andrew Humphreys
    Level 1 (0 points)
    Apr 3, 2014 7:32 AM in response to Andrew Humphreys

    In 3 words: Thanks! Thanks! Thanks!

     

    Adjusting the voltage to 0.98 did it, and I'm working again at last.

    Once more, now in portuguese: Obrigado! Obrigado! Obrigado!

  • by hamah,

    hamah hamah Apr 5, 2014 11:46 AM in response to cimbalino
    Level 1 (0 points)
    Apr 5, 2014 11:46 AM in response to cimbalino

    I'm going to bet that within days,weeks, or months your problem will, unfortunately, return. I tried all of the suggestions and ultimately the only thing that seems to have resolved the issue was to replace the GPU.

  • by Johann P,

    Johann P Johann P Apr 6, 2014 10:58 AM in response to hamah
    Level 1 (0 points)
    Apr 6, 2014 10:58 AM in response to hamah

    Yep. Now is the perfect time to backup your hard drive and wait for the inevitable... while you can still see what's on your screen.

  • by cimbalino,

    cimbalino cimbalino Apr 15, 2014 3:02 PM in response to hamah
    Level 1 (0 points)
    Apr 15, 2014 3:02 PM in response to hamah

    Yeap, you were right... the black screen came back to my mid 2010 27" i7 iMac!

    Nevertheless there's something bugging me:

     

    1. If I connect the iMac to an external monitor, the external monitor displays the image perfectly for days
    2. If I boot with other OS via bootcamp, the iMac works and no black screens
    3. If I disconnect every cable, remove ram, do all resets and wait 10 minutes with the iMac unpluged from electrical power, it comes back to life until next random black screen; unpluging is crucial!

     

    Which made me think that:

     

    1. External monitor works - no GPU problem
    2. LCD works with other OS - no LCD problem
    3. Firmware / static / power issue?

     

    I'll try the "you-bet-this-is-a-true-grounded-plug" solution tomorrow as well as one RAM module at a time before even considering spending cash on replacing hardware.

  • by cimbalino,

    cimbalino cimbalino Apr 28, 2014 1:57 PM in response to cimbalino
    Level 1 (0 points)
    Apr 28, 2014 1:57 PM in response to cimbalino

    Just to let you know:

     

    I've changed the iMac connection to a new one which does have ground.

    Did a ram removal and left it unplugged for 1 hour.

    PRAM reset.

    It's been two weeks and it's working flawesly.

     

    Hope this info is useful.

  • by Scott Bedford,

    Scott Bedford Scott Bedford Jun 11, 2014 3:33 AM in response to rubenlx
    Level 1 (0 points)
    Jun 11, 2014 3:33 AM in response to rubenlx

    You can add another to the list of faulty Mid 2010 iMac's. Mine has been playing up for the past few months and I've just come across this thread.

     

    Exact same issue as everyone elses on here with artifacts and freezing.

     

    Does anyone know what Apple charge for a GPU replacement?

  • by Carl Ketterling,

    Carl Ketterling Carl Ketterling Jun 11, 2014 2:28 PM in response to Scott Bedford
    Level 1 (19 points)
    Jun 11, 2014 2:28 PM in response to Scott Bedford

    Scott Bedford,

     

    I paid about $175 for a GPU replacement.

  • by Scott Bedford,

    Scott Bedford Scott Bedford Jun 12, 2014 2:42 AM in response to Carl Ketterling
    Level 1 (0 points)
    Jun 12, 2014 2:42 AM in response to Carl Ketterling

    Spoke to my local Apple approved repairer today and was quoted $600 AUD to get it replaced. Quite an Australia tax!

     

    The iMac was nearly unusable today with freezing and crashes so need to get something done. Will make the 1hr 30min trek to the Sydney Apple Store tomorrow and see what they say.

  • by Studio K,

    Studio K Studio K Jun 12, 2014 10:33 AM in response to Scott Bedford
    Level 2 (355 points)
    Jun 12, 2014 10:33 AM in response to Scott Bedford

    I use SMC Fan Control app to set the minimum fanspeeds higher.  This keeps the iMac cooler and helps avert heat-related crashes.

     

    My GPU froze nearly every day.  After increasing the fanspeeds, I've gone 2 months with only one freeze (which prompted me to raise the fans a bit more).

     

    It seems to make a difference and is a solution that costs no money.

  • by TheGuyintheProjectionBooth,

    TheGuyintheProjectionBooth TheGuyintheProjectionBooth Jun 12, 2014 2:16 PM in response to Studio K
    Level 2 (208 points)
    Mac OS X
    Jun 12, 2014 2:16 PM in response to Studio K

    I'm having to do the same thing on my early 2008 MBP.

    Studio K wrote:

     

    I use SMC Fan Control app to set the minimum fanspeeds higher.  This keeps the iMac cooler and helps avert heat-related crashes.

     

    My GPU froze nearly every day.  After increasing the fanspeeds, I've gone 2 months with only one freeze (which prompted me to raise the fans a bit more).

     

    It seems to make a difference and is a solution that costs no money.

  • by Johann P,

    Johann P Johann P Jun 12, 2014 6:06 PM in response to Studio K
    Level 1 (0 points)
    Jun 12, 2014 6:06 PM in response to Studio K

    I did that too... as well as a load of other things... it lastes a few months until I had no choice but to change the GPU. There's no other way around it... as this thread proves.

  • by TheGuyintheProjectionBooth,

    TheGuyintheProjectionBooth TheGuyintheProjectionBooth Jun 12, 2014 8:45 PM in response to Johann P
    Level 2 (208 points)
    Mac OS X
    Jun 12, 2014 8:45 PM in response to Johann P

    My MBP had the notorious "flickering" screen that Apple had a 4 year extended (12-12-12) GPU replacement warranty on it. Too bad the person that owned this before me didn't know about it and had it fixed. I have been told that it'll cost $400 to fix it. I got an extended warranty when I bought this just in case. Good thing. So next week I'm filing for repair. But I think it will also fix the dropping WiFi. It's been said that a component that is failing and taking the WiFi with it is on the GPU board that will be replaced. Fingers crossed. One thing though, when it fails the deck above the F keys gets so hot it's difficult to touch. That's why I keep the fans running so high. Strange what fails in Apple gear?

  • by Revgap,

    Revgap Revgap Jul 5, 2014 2:23 PM in response to paulmcg123
    Level 1 (0 points)
    Jul 5, 2014 2:23 PM in response to paulmcg123

    Thanks for you posting paulmcg123,

    My 2009 iMac 27 would only boot in safe mode leaving me to struggle to figure out the problem. I also had no sound device and video would not play. I replaced Hard Drive (went bigger). Problems remained. That left me to consider whether logic board, graphics card or both were bad.

     

    Seeing your post I removed the ATI2000 extensions. The machine completed start up, sound device (and sound) was back and video played. The video still shows choppiness when videos played. I will continue to figure out. But thanks to your discovery and post my machine is back.

     

    Thanks

  • by Climberfx,

    Climberfx Climberfx Jul 7, 2014 7:21 PM in response to rubenlx
    Level 1 (0 points)
    iPod
    Jul 7, 2014 7:21 PM in response to rubenlx

    We wanna a recall!!!

    Some time ago, they call recall for the i7 models from 2011, mine is a i5 from mid 2011.

    After 3 years of normal use, My machine start to get worst every day. But isn't only the squares pipocating on screen, it lock and freezes, and the only way to use again, is with physical restart.

    I call for phone support on Brasil, and the operator checked my serial and told me that mine isn't on recall.

    Sad, because this is a malfunction, and need to be replaced.

    Apple before Steve jobs, was more serious then now.

    I wanna my money back. Or a new machine without bug.

    3 years is a young machine. In the past, mac works for life. I see a lot of power pc still on function.

    This is not a user caused problem. A lot of people complain about the same defect.

    This is not a cheap machine!

    We need to be heard! Where is that Apple from Steve?

    Where is my recall, APPLE????

    Shame on you!

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