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Agile55

macrumors 6502
Jul 18, 2008
252
73
TX
IMac screen is darker on one side than the other, Just before shutdown does anyone else have this?
imac 2020 5700xt
Good to see I'm not the only one w/ this as the left 1/2 of my screen vertically does the same just before shutdown on my 2020 retina 5K 5300 iMac (27").
 
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Agile55

macrumors 6502
Jul 18, 2008
252
73
TX
IMac screen is darker on one side than the other, Just before shutdown does anyone else have this?
imac 2020 5700xt

So in 12 hours since the OP posted the above we're the only 3 here that have this issue ....... hmmmm .................
 

wilberforce

macrumors 68000
Aug 15, 2020
1,688
1,559
SF Bay Area
So in 12 hours since the OP posted the above we're the only 3 here that have this issue ....... hmmmm .................
A bunch of people in this thread observed the same thing:
 
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fjho2000

macrumors newbie
Dec 29, 2020
7
2
1609289357902.png

Is the issue like this just before shutdown? If so, I have it too and so far no solution to my 2020 imac 27” after resetting PRAM, or reinstalling macOS Big Sur, or resetting SMC. I turned it on in safe mode and it didn’t do it.
 

DLary

macrumors regular
Oct 21, 2005
125
20
Turning off True Tone virtually eliminates it. I'm not sure it is a problem, as it only occurs on shutdown. Maybe the iMac treats the screen as side by side 2560 x 1440 displays and one side shutdowns first or faster?
 
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fjho2000

macrumors newbie
Dec 29, 2020
7
2
I just turned off True Tone to test if that was the case and the issue still happened, so in my situation at least it’s not due to having True Tone off. Also in my case, if I turn it on and turn it off within 5-10 minutes, the issue doesn’t happen and the dock hides all the way (which it hides halfway only when it happens). Don’t know if others have a similar experience (there is one picture from the other thread pointed above that has the dock halfway down).
 
Last edited:

myjacob

macrumors member
Aug 19, 2020
44
20
Hmm.. I downloaded Diablo 3, and after first run I changed resolution from 5K to 2560x1440, pressed “Apply”, and got half screen darker in the game. Command-Tab two times eliminated this. Super weird.
 

ifd66

macrumors newbie
Dec 31, 2020
1
0
I have exactly the same problem as reported in this thread. New iMac 27" running Big Sur. Have reset PRAM, and opened in safe mode - after both procedures it shut down normally, but then reverted to the suffering from the split screen during shutdowns.
 

Thewadeyo

macrumors newbie
Jan 3, 2021
1
0
Well mine is constantly darker on one side than the other. Anyone know of a fix? If it’s been off for a while then it’s not there but if I’ve been editing or machine idles for some time then it returns. 2020 5k iMac 5500xt. See image. Tried to find a way to best show the Line directly down the middle, top to bottom. one half darker than the other.
17075609-E352-4FEF-A465-44087924081D.jpeg
 

jtaylorau

macrumors member
Original poster
Jan 15, 2014
69
13
now had two Panic in last week nothing much open
Panic(cpu 2 caller 0xffffff7f9bf455f2): "[3:0:0] GPU Not Found! PCI Config Access Fails!!!


"@/AppleInternal/BuildRoot/Library/Caches/com.apple.xbs/Sources/GPUDriversAMD/GPUDriversAMD-4.2.13/Common/IONDRV/ATI/AMDUniversalFramebuffer/AMDUniversalFramebuffer/Controller/Controllers/AmdRadeonController.cpp:1790


Backtrace (CPU 2), Frame : Return Address
 

fjho2000

macrumors newbie
Dec 29, 2020
7
2
As I have reinstalled MacOS, as well as reset PRAM, SMC, and it continues to happen, I have set up an appointment at Apple so they can check what is wrong with it as they don’t know at this moment if its hardware or software related. Ill share what happened afterwards.
 
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fjho2000

macrumors newbie
Dec 29, 2020
7
2
Took it to the Genius Bar and they couldn’t replicate the issue (they weren’t clear if they left it on for over 30 minutes or longer and if they turned it on on safe mode). They wiped out the drive and reinstalled the original macOS (Catalina) while their diagnostics didn’t show any issues with hardware/software. I got it back and reinstalled all my files with Catalina on and turned it off after an hour and the issue didn’t happen. Went ahead and upgraded to Big Sur and it happened again. I wiped out the drive again and without installing my files from back up, just upgraded directly to Big Sur as if a new computer and to ensure it had nothing to do with any corrupt files and after leaving it on for over an hour, the issue happened again. I will send info to Apple, but if there are no issues with hardware, I suspect it’s a software bug - though the Apple employee said he had not seen any info at Apple on this issue so far.
 
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jaynemjay

macrumors newbie
Jan 31, 2021
1
0
Well mine is constantly darker on one side than the other. Anyone know of a fix? If it’s been off for a while then it’s not there but if I’ve been editing or machine idles for some time then it returns. 2020 5k iMac 5500xt. See image. Tried to find a way to best show the Line directly down the middle, top to bottom. one half darker than the other. View attachment 1706077
I have exactly the same issue! iMac 2020 5300. Also when I wake the mac up from sleep the screen is completely dark on one side for half a sec on the login screen. Did you found any solution for this?
 

LadyNinja

macrumors member
Aug 6, 2020
61
18
Norway
Me too. Check/uncheck the true tone off/on makes it disappear for me. I have the faint line in the middle, best seen on grey. Thats my resolution when im editing images.
But after turning off adjust brightness automatically, i think i only once or twice after that, saw the line. But waiting for it. Now both brightness and true tone are off. Before I got the problem up more often.
Pretty sure this can be fixed with an software update.
All the bugs with this machine, like re-eventing the wheel... Dont forget the glitch we had on the i7. But at least it got fixed.
 

jtaylorau

macrumors member
Original poster
Jan 15, 2014
69
13
onsite service the logic board & screen replaced haven't upgrade to big Sur yet
 

jtaylorau

macrumors member
Original poster
Jan 15, 2014
69
13
Have other systems can afford to wait to update to Big Sur on iMac 2020 this time around
 

jtaylorau

macrumors member
Original poster
Jan 15, 2014
69
13
Took it to the Genius Bar and they couldn’t replicate the issue (they weren’t clear if they left it on for over 30 minutes or longer and if they turned it on on safe mode). They wiped out the drive and reinstalled the original macOS (Catalina) while their diagnostics didn’t show any issues with hardware/software. I got it back and reinstalled all my files with Catalina on and turned it off after an hour and the issue didn’t happen. Went ahead and upgraded to Big Sur and it happened again. I wiped out the drive again and without installing my files from back up, just upgraded directly to Big Sur as if a new computer and to ensure it had nothing to do with any corrupt files and after leaving it on for over an hour, the issue happened again. I will send info to Apple, but if there are no issues with hardware, I suspect it’s a software bug - though the Apple employee said he had not seen any info at Apple on this issue so far.
how u going with issue found a fix yet ? 2 logic board. replacement read also affect other OSs, AMD/Apple shouldn't released the 5700 xt in it's current state
 

costica1234

macrumors regular
May 21, 2013
186
126
I have the regular 5700 (non XT that is) and I've noticed this issue only before shutdown (both on Catalina and now on Big Sur). It doesn't bother me much, but it's concerning to hear that some folks have one side darker / brighter than the other during normal use...
 

fjho2000

macrumors newbie
Dec 29, 2020
7
2
Updated to big Sur 11.2.2 and still have the same issue at shutdown. I have reported it as well through the Apple support feedback (https://www.apple.com/feedback/) and sent an email to higher-ups several weeks ago and got a call back that they have provided with this to Apple’s engineers, but the person said he didn’t believe it’s a hardware issue from the description and photos I provided with, though so far no fix with latest update. At the Apple Support Communities one user is recommending downloading and checking it with Etrecheck. Here is the link to the user’s recommendation: https://discussions.apple.com/thread/252114918?page=2
 
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