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

I decided to cancel my order with the 5700XT as it seems even people getting them now have issues. I’m not a gamer and I decided to re-purchase with the 5700 regular which should be enough.

I also went from regular to nano glass, as,my desk is located,next to a window and I think this will cut down on glare and washout from the sun. Seems the jury is mixed in this glass. Some say it’s amazing others say it’s not worth it and some say it has viewing angle issues and makes text harder to read.

Is there any consensus as to if this is a hardware or software issue? It sounds like a software issue but with people being to,d to return their units for new ones... that sounds like a hardware issue. However it just may be standard to tell people that having issues.

any thoughts on what it is?

Have had my iMac 2020 with i9, 5700XT for about a week now and the white line glitch was annoying the life out of me. Sometimes blinking on the left side, other times on the right. Sometimes it would occur every five minutes, other times only once in an hour or two.

There are a couple of known workarounds so far, based on comments across the internet, from users affected by this glitch:

1. Connect a second screen

Apparently connecting a second screen somehow completely eliminates the glitch. I personally don't want to attach a second screen and trying to use a headless HDMI plug didn't go well (causing bluetooth lag). So that's a no go for me.

2. Change the screen resolution

Users reporting that the glitch is gone with any resolution other than the default 2560x1440. So yesterday I created a custom resolution 2528x1422 in SwitchResX, switched to that, and I have not seen the white line glitch since then. Has been just over 24 hours now, glitch free 🤞

That's more than one could ask for. I only play "Civilization VI" myself (not an easy game to play out of the box), but I believe another user in this thread had the same problem with "Skyline" - I see both are available as a demo on Steam. I totally understand if that is too much of a hassle for you. :-)

Ok, hmm, Civilization has a demo available only on Windows and not sure if by "skyline" is meant Cities:Skylines or Infinite Skyline. Neither of them have demos anyway though.

Went and downloaded the first f2p I could google and installed StarCraft II. There in settings couldn't even select my custom screen resolution, only the given OS defaults.

So I guess this SwitchResX workaround won't be any good for gaming, by the looks of it

Thanks for the effort nevertheless. I must wait for people to confirm when the thine line glitch has been fixed, then re-order my iMac and hope for the best. 128 GB third-party RAM just collecting dust in the drawer - very frustrating.

I've been waiting for a new iMac model for a long time. But I'm not going to pull the trigger on a new one until this issue has a resolution. I'd be ok if I was just assured that it is a software issue.

But I certainly don't want to deal with a hardware hassle with a brand new unit. Is there a place where Apple can have people like me voice their concerns? It would definitely help to define how much $$$ Apple is losing based on this issue and help to prioritize efforts to resolve it.

Apple has reached out to some of us for gathering information so they are looking into it, but I wouldn't expect them to come out and announce whenever/whatever the specific has been fixed whenever that situation might arise. The hardware concerns are what made me return my unit.

I must admit - I'm not surprised. I bought my first iMac in 2006. It was repaired after 2 years replacing the logic boards I think they called it. After this is actually didn't last long before the graphics adapter stopped working again. This time I could not get a repair since it was more than 5 years old.

I bought a new one - don't recall when. The graphics adapter went dead after a few years on that one - 2-3 years. If you know the oven trick - I used that to repair it - twice. 3rd time wasn't a charm.

Replaced it with my current iMac which have serious image retention issues.

The quality is just way too bad and luckily I searched here and there before ordering a new one which is kinda due. It's just sad to see such a respected company time and time again presenting such poor quality computers.

Might not be that helpful but I just had to get this off my chest.

Common advice for any iMac especially...

Have you blown the dust out of the intakes lately?

What temperatures does this App report? Especially the GPU.

This App can be used to speed up the fans, all my iMacs would be dead without it.

Never ever ever drop fan speeds below the speed that the Mac itself is calling for.

MacFansControl…

https://www.crystalidea.com/macs-fan-control

Besides having the line glitch randomly popping up across the screen, another thing I notice is that the fan is constantly on, even when idle. I work in a quiet space so its more noticeable. Is this normal? my previous iMac's were quite and only heard the fans when rendering videos in fcpx.

Here's what I captured on video, even before I had a chance to setup my " New" iMac. This line glitch continues to happen. This is my second unit that replaced my first one with the same issue.

https://youtu.be/x83_QzLlv9Y

Here's what I captured on video, even before I had a chance to setup my " New" iMac. This line glitch continues to happen. This is my second unit that replaced my first one with the same issue.

https://youtu.be/x83_QzLlv9Y

I get this too. White horizontal lines... a few times an hour. iMac 2020, i7, 8GB (so far, come on Crucial) and 5700 XT 16GB.

On the whole it's annoying, but not a disaster. Hopefully Apple will have something useful to say. Come on, Apple!

I cancelled my iMac 2020 5700XT (3.8GHz 8-core i7) order as soon as I read about this graphic glitch issue, which I've noticed has since been reported on many tech websites! It's so frustrating! Yes, it may be a minor issue (to some), but it eradicated my excitement and total enthusiasm of getting an iMac for the very first time. I won't be re-ordering until there's some acknowledgement from Apple and some traction over what is being done to resolve it.

I could order the 5700 graphics instead, but then I'm giving Apple my money for a less powerful machine, especially as I want to play games in bootcamp (Windows), and also feel like it's letting Apple off the hook over a QC issue.

I'm also annoyed to read many new iMac 2020 owners saying they are hearing the fan even when idle, as apposed to the iMac 2019 which was dead silent during idle. I'm used to my quiet MacBook Pro 13" Early 2015 which is silent 99% of the time! Someone mentioned the fan sounds like someone breathing with their mouth open, even during idle. Can anyone confirm if that seems correct?