Graphical Glitches Plaguing Some 2020 iMac Owners With Radeon Pro 5700 XT GPU
Apple in August refreshed the 2020 iMac lineup with a new 27-inch model that's equipped with 10th-generation Intel processors, more RAM, more SSD settings, and faster AMD GPUs.
Unfortunately, some new Mac owners have been running into problems with their machines and have been reporting ongoing glitching with the graphics. There's a 57-page thread on the MacRumors forums filled with complaints dating back to August, suggesting this is a problem that's been impacting iMac owners since the new Macs came out.
Based on a poll, a good number of iMac owners who have the higher-end 5700XT GPU are seeing a white horizontal line flicker across the display on occasion, but the problem does not seem to impact all users.
MacRumors reader
torifile describes the issue:
I got my 2020 iMac Thursday night. It's as fast as expected and gorgeous. Last night I thought I saw, out of the corner of my eye, a horizontal white line flash mid-way up the screen. It was really fleeting and I thought I was just seeing things. This morning, I saw the same thing. The computer isn't running hot or anything. iStat Menus has all the cores untaxed. I recall having this same problem with my MBP 13" (2019) with an earlier version of macOS (I can't remember if it was a late Mojave build or an early Catalina) and it was cleared up with a software update.
The white line described by those affected appears to flash across the screen at random intervals throughout the day, and there are some other seemingly related graphical issues that iMac owners have run into. Some users have reported being able to remedy the problem by choosing a scaled resolution other than the default, but that's not an ideal longterm solution.
It's not clear if the issue that iMac owners are experiencing is hardware or software based, but Apple has not yet implemented a fix for the problem.
Popular Stories
The iPhone 17 Pro and iPhone 17 Pro Max are around three months away, and there are plenty of rumors about the devices from credible sources.
Below, we recap key changes rumored for the iPhone 17 Pro models as of June 2025:Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone X...
Last week, we reported that iOS 26 introduces an opt-in Adaptive Power Mode on the iPhone, alongside the existing Low Power Mode.
Apple says that Adaptive Power Mode can make "small performance adjustments" when necessary to extend an iPhone's battery life, including slightly lowering the display brightness or allowing some activities to "take a little longer."
The full description of...
Apple has long been working towards an iPhone with an all-screen design, and it might finally achieve the feat in a few more years from now.
In his Power On newsletter today, Bloomberg's Mark Gurman said that Apple will shrink the size of the Dynamic Island on new iPhone models released next year. A year after that, he expects Apple to release a redesigned 20th-anniversary iPhone model....
Apple provided developers with the second beta of iOS 26, introducing the first changes and refinements to the new operating system since it debuted after the WWDC keynote. Because we're early in the beta testing process, there are quite a few tweaks to iOS 26, which we've rounded up below.
Control Center
The background behind the Liquid Glass Control Center buttons has more blur, allowing...
With the second beta of iOS 26 that Apple provided to developers today, Apple addressed one of the major complaints that people have had with Liquid Glass.
iOS 26 beta 1 on left, iOS 26 beta 2 on right
The Control Center buttons are now slightly more opaque, making it easier to see the different control options even on a multicolored background. The new, more opaque look is apparent with the ...
Apple's upcoming iPhone 17 Pro and iPhone 17 Pro Max models are rumored to be equipped with a vapor chamber cooling system, and a leaker known as Majin Bu today shared a photo of an alleged copper thermal plate for the system.
Many high-end Android smartphones like Samsung's Galaxy S25 Ultra are equipped with a vapor chamber cooling system, which can manage heat dissipation inside the...
iOS 26 is gaining two new Wi-Fi features, including Captive Assist and Wi-Fi Aware.
MacRumors contributor Aaron Perris discovered a reference to Captive Assist within the code for the first iOS 26 developer beta, but Apple has yet to enable the feature. It should be available by the time the software update is released later this year.
In his Power On newsletter last month, Bloomberg's...
While the dust is beginning to settle on the first iOS 26 beta, we continue to take a closer look at new features coming with the update.
Below, we recap five smaller changes that you might have missed.
Emoji Game
Apple News+ subscribers in the U.S. and Canada can play a new Emoji Game, which tasks players with completing words and phrases with emoji.
This is the fifth game that is...
Apple is running a new promotion that offers free AirPods to qualifying customers.
Now through September 30, college and university students in the U.S., Canada, Mexico, and Singapore can receive free AirPods 4 when they purchase an eligible new Mac or iPad from Apple. AirPods Pro 2 are also available at a discount.
If you do not want AirPods, the promotion also offers various other...
