2011 iMac odd graphic corruption

mbritto.fr

macrumors newbie
Dec 21, 2019
2
0
I had the same issue you guys had 18 months ago and it got so bad sometimes the glitches started during the startup when the screen was still gray.
I saw a youtube video of a guy recommending to cook the graphic card in the oven (for real). He said the graphic card was desoldered and the heat would fix it. I was about to throw my iMac away so I tried it. The longer was to access the graphic card and take it out, then 8min in the oven and I put it back in the iMac.
it worked! For the last 18 months the iMac was working...then it started back.
I will probably use it as an external screen now but it would maybe work again with the oven hack. You can find many YouTube videos of guys telling you how to do it. If this is the same problem I had it may work for you but it could also “cook” your graphic card so try it as your last resort
good luck
 

DJR5985

macrumors newbie
Feb 11, 2020
2
0
I know this is an old thread but I wanted to chime in here. I have a mid 2011 21.5" iMac with the AMD 6750 M running Sierra 10.12.6 and have been dealing with this issue for over 2 years (upon transitioning from mountain lion to Sierra.) I did have a power supply slowly die in this machine that I replaced with a pull from a working iMac, and that fixed the power issue but the pixelation and glitches started after upgrading to Sierra and seemed to be un-related to the power supply.

This issue has slowly gotten worse over time. I have never been higher than 10.12.6 because my audio software is only compatible with this OS so I'm at an impasse. I have spent the last week trying to diagnose and figure it out. As with the above posters, the computer runs flawlessly in safe mode and the internal Mac hardware tests come back reporting the GPU as "ok." I have tried a clean install of Sierra on a separate partition of the HD but that still produces graphic glitches. 3-4 days ago, the computer had gotten so bad it was unable to even boot into the desktop without locking and crashing.

After removing some larger files from the internal HD and doing some general cleanup, doing some first aid on the partitions I started looking for software issues, particularly things that may have been causing kernel panics. As of today, I've gotten the computer to actually run on my normal Desktop (not safe mode) and that only occurred after disabling some startup processes and/or LaunchDaemons and going through the kexts looking for issues. I've gotten the computer back to a more intermittent graphic issue where I'm typing this on it in Safari at the moment with no issues.

For previous or future posters that may read this, I'm wondering out of curiosity if any of ya'll have (or had) Adobe products on your machines? Specifically the CreativeCloud and any graphics programs (photoshop, indesign, acrobat) because I'm starting to suspect those are at very least contributing to the problem. Disabling most of the adobe background services and removing a couple adobe cache/plist files as seemed to improve things which makes me curious. I have multiple AdobeCRDaemons that run no matter what I do and a kerneltask process is often using up a ton of memory (I have 16GB) without anything Adobe even open (so not sure what that's about.) At very least, Adobe is a resource hog and drives me crazy. I make an attempt to quit all those processes when I start the computer. My next step will to be completely removing ALL adobe software and any remnants to see if that has any impact followed by a total system wipe to factory default, and back to a fresh install of Sierra.

Like many of you my troubleshooting efforts seem to lead me to believe this is some kind of software related conflict, particularly because in Safe mode there is not a SINGLE trace of the pixelation or glitch issue whatsoever as highlighted in this thread. In the past I can also confirm that maximizing an app or safari window would temporarily solve the issue, but then that no longer worked. I also found that when things started to get really bad putting the computer to sleep and then re-waking it would fix the issues temporarily. Additionally, I find that when using Pro Tools (which is an insanely resource heavy audio recording program) with windows on two different screens and a lot of information flying around, the issue was barely present if at all (which is a head scratcher.) Based on information around the web about this AMD card it wouldn't surprise me that the issue is related directly to it and/or it's drivers, but it sure seems like manipulating things in the software realm has an impact on the problem. If I can't figure out a fix I guess it may just be time to put this thing to sleep permanently, but she's had a good run.
 

Richdmoore

macrumors 68000
Original poster
Jul 24, 2007
1,786
254
Troutdale, OR
I did not have any adobe products on my computer (when I still owned it.)

I was able to confirm temperature affected the condition on my computer (I put it in a dry but cold non-heated garage to test.)

Hopefully your issue is software and not hardware, but the temperature test pretty much confirmed mine was not. (The iMac was sold to gazelle for parts or them to fix.)
 

DJR5985

macrumors newbie
Feb 11, 2020
2
0
I did not have any adobe products on my computer (when I still owned it.)

I was able to confirm temperature affected the condition on my computer (I put it in a dry but cold non-heated garage to test.)

Hopefully your issue is software and not hardware, but the temperature test pretty much confirmed mine was not. (The iMac was sold to gazelle for parts or them to fix.)
Thanks for the reply. I am gonna try everything I can but at the end of the day, an upgrade is probably inevitable.
 

mbritto.fr

macrumors newbie
Dec 21, 2019
2
0
This is most definitely an hardware issue : the GPU has troubles when it is under too much load. The fact that it works in SafeMode doesn't rule out an hardware issue, because the Safe mode uses the graphics card at its minimum level. Some apps (Adobe in your case, or even newer macOS versions) may use more GPU intensive tasks and triggers some glitches.
Sometimes issues are pink vertical lines, other times they are graphical glitches. When they first appear they are rare, but the more you wait, the more they will appear until your imac becomes unusable.
I've had those issues twice : 18 months ago, I fixed them by following this guy's video :
I put the graphic card in the oven (for real) :D
It worked flawlessly...for 18 months.
Issues came back last month : cooked it again and it worked...again.
I'll see in 18 month if it comes back :D