iMac 27 inch 2020 - Screen Glitch (Random Lines Appear on Screen)

Same here. At first I only had the flickering/sharp corner on selected apps. Then after 2 weeks of use I have got 4 instances of the white line within 4 hours of use. Any knowledge on how you can trigger it? What are you guys doing when it happens?

I have the 5700xt

Specs: 27" iMac 2020, 3.8GHz i7, 64GB RAM, 1TB SSD, 5700XT GPU

Exactly the same issue for me! I can confirm the issue persists after starting in and out of Safe Mode, resetting the PRAM/NVRAM and SMC. It also happened whilst using 8GB RAM, 64GB RAM and a combined 72GB RAM (I believe this combination of different RAM sizes puts the system into single channel mode). Because the issue is a random white horizontal line flicker it is a lot less noticeable if you switch from Dark Mode to Light Mode, but still still happens nonetheless and is extra noticeable in programs like Final Cut Pro X which has a "dark" design by default.

I'm sure we'll all be watching for an update asap, because this issue is driving me crazy and the Mac will have to go back if there isn't going to be a software fix!

I have the 8GB ram, would adding another 8GB in another slot help? I'm concerned with the apparent randomness in frequency in which the glitch happens in different peoples' system, I use dark mode on a dark desktop with Dark Reader plugging for safari, and notice the glitches 4-5 times a day on a bad day, and none on a good day, I have another week to decide to return it.

I have the 8 core 5700XT, 2TB, 10G ethernet, nano matte display

That will not help. I had 4x32GB before I returned my unit and I had the same issue. I'm pretty sure that it is purely a problem with the XT GFX, but whether it is a software or hardware issue (or both) still appears unknown. We can only hope that those of you keeping the unit can report the issue fixed by a software update.

It Does, I noticed in Dark mode it was easier for the glitch to catch the eye. However, I also noticed that the glitch in dark mode sometimes came across as a lighter gray color (but still was more noticeable). In non dark mode it was a whitish glitch for me, in Dark mode (Well not the first unit) was more a bright gray, The Second unit it would by a near white or a bright white... I have since sent them both back and hoping they figure it all out.

Ok that suggests it’s a software/driver issue based on the glitch appearing in relation to cursor and active window positioning, as apposed to the glitch appearing across the entire screen irrespective of the active window and at irregular locations - that would suggest a hardware issue. I hope Apple comes up with a software fix soon! This has been happening for a while now.

Confirmed (at page 58): https://forums.macrumors.com/threads/imac-2020-5700xt-graphical-glitch.2251034/post-28921285 .

Evidently, the 2020 iMac 27 was not compatible with the Preview versions of Big Sur until beta 6.

Has anyone heard, seen or know of any news/updates from Apple in regards to this issue? I see they are still selling the 2020 iMac with the 5700xt 16gb option, but wondering if they are still riddled with all the issues.. I personally have not heard anything back from apple on my case (but then again i sent the replacement unit back for refund).

Was just curious if there were any mentions of a possible root cause or ETA when it will be fixed...

Thanks in advance

When I was dialog with Apple (some weeks ago) they were less interested in the random lines glitch and had much more focus on the entire system crash that I experienced on my unit when playing games. Their focus can of course have changed since then, but when they called me up that was the main concern as I understood it. Now I wonder if I should order a new unit with a non-XT GFX, but would that GFX be able to play any sorts of games? Looks weak compared to the 16GB XT.

I dont think these are in general “riddled with issues”.

It seems like all of the 5700XT models have the flickering squared corner on some apps. It seems very reproducible. And all have to some degree the white line. Mine didn’t show any white line for 2 weeks. Then 4 times in a day and now nothing for several days. Other seems to have it nearly hourly. Maybe I’m half blind or less observant, but it seems odd.

The serious issues with kernel panic and so on I think (hope) is limited to relatively few users/machines. I haven’t had a single instance. If that happened frequently on my new mac I would insist on a replacement as this would indicate faulty hardware unless it’s solely related to specific non-apple signed software.

I've been holding off an order until I hear that there is a resolution. But I've been thinking about ordering a unit without the 5700XT. Almost all of the chatter I hear is from the 5700XT and the white lines. Can anyone verify that the white line issue exists on the non-5700XT units?

I can confirm that the 8gb 5700 model, 8core intel (the one I am on now) runs like a dream, no issues with screen glitches etc. it is also super quiet. I decided to go for this and not have the headache of the glitching. And you know what, I have no regrets, it is a capable machine. I hope that helps.

There are 13 pages of posts. Perhaps it would be best if Apple stopped selling this configuration since people seem to keep buying it, only to be unhappy and exchange or return it. Pull it now and limit the number of machines Apple with have to replace when someone finally figures out what the problem is.

There are engineers all over the planet who think this machine will never be a success due to the poor cooling system. As they say the flaws could find a source in the fact that the components inside the case are continiously overheating. this will as well shorten the live span of the machine. And if this is the reason Apple is in big trouble because they have to come up with a new design of the inner working which can mean a long delay of reintroducing the machine. For now this is still theory but you never know....

Hi(Bonjour),

I think that the white line problem and the square corner issue are not related to the same cause as the loud fan. I see the white line once, but despite heavy compression job in Compressor, my fan is quiet. I own the 5700XT 16 Go GPU.