White Horizontal Line on new 2020 iMac with AMD Radeon Pro 5700 XT 16 GB graphics card

I would like to make a suggestion that is to get in contact with Apple Support Directly either by calling them or by making a appointment for the Apple Store for them to take a look at it! Since it is only a week old and you spent a lot of money for it let them take a look it. It does sound like you have a Hardware Problem with it but that is only my opinion!

You can raise your issue here until you are blue in the face, and the Apple product teams, and retail outlets that do not participate here will never see your post. These are fellow user supported communities, and aside from an occasional Apple badged community specialist helping out, they are not members of the product teams, and are not a conduit for hardware evaluation issues.

It was already mentioned earlier about the process of actually contacting Apple, or an Apple Authorized Service Provider to get your hardware evaluated, or if within 14 days of purchase, returning the product.

We see similar issues with new releases of hardware and software so please call AppleCare and if necessary take the computer in to your local Apple Authorized Service Provider. Please follow the proper steps. This is what Apple is going to ask you to do anyway. Perhaps others are experiencing similar issues, okay. Just letApple know and work with them to help resolve the problem. Remember you have 14days to return the computer and either get your money back or exchange it.

Apple needs a bit of time to see if this is a wide spread issue, analyze it to see if they can replicate it and then work on a fix. This all takes time. So please just follow the correct steps and contact AppleCare.

I understand, so take screen shots of the issue when it occurs and then contact AppleCare and show them the screen shots. You have an option to return the computer if it is 14 days or less old and was purchased directly from Apple. Jon, if the issue is that concerting to you then this may be an option you should consider.

I received my brand new iMac Wednesday with the same configuration and I experimented exactly the same problem.

Today I called Apple Support.

The support told me:

• the problem is known internally by Apple. The internal issue had been released yesterday (afternoon, around 3:00pm)
• engineers are working on these random horizontal white lines / 5700 XT 16Gb
• we don't know if problem is related to hardware or software

I don't know what to do with my brand new iMac :

• Option 1 : return to Apple Store and ask for a new iMac with a cheaper graphic card (but working!)
• Option 2 : hope the problem is software and wait for next FIX.

If the problem is hardware I will own an iMac defect by design for many years...

Good morning Jon,

yeah you are not the only user experiencing the problem! Actually there is a second thread to Apple Discussions website which provides a few more statements: https://discussions.apple.com/thread/251730390?login=true

It's hard to grasp on the problem as the glitch / tearing / flickering just occurs randomly. I wouldn't call it minor either. It simply is frustrating. I can screen record one day for 2 hours and nothing happens. On the next day the flicker happens like 3x times in a row within a few seconds :X

Also iMac 20,2 27" + 3,8 Ghz i7 + Radeon Pro 5700 XT

What does AppleCare say?

Renee, it only affects machine with the AMD Radeon Pro 5700 XT 16GB GPU, all other machines are just fine. My configuration is the standard GPU, the AMD Radeon Pro 5500 XT 8 GB and it is 100% okay.

This graphical glitch issue is quite concerning and is preventing me from buying the top of the line iMac 27" 2020 with the Radeon Pro 5700XT graphics. And according to the macrumors forum I'm not the only one! It seems there's a lot of potential buyers holding off until there's some acknowledgment and solution from Apple.

These computers are brand new, less than a month from their initial announcement. While my new 2020 27" iMac does not have the RP 5700 XT it works perfectly. If the problem is wide spread then you can be assured Apple will address it as quickly as they can come up with a solution, this is what they have done historically when other new products have had an issue.

I bought and then received my “top of the line,” maxed out 2020 27” 5K iMac, last week, with no problems. I never heard of graphic issues until now, my iMac is still working okay!