Occasional red squares on iMac 2017

[henryaaron]

I have a 27" iMac from 2017. The graphics card is Radeon Pro 580 8 GB

Occasionally, while switching windows or tabs. Large parts of the screen will flicker pure red. It's a single flicker, it lasts about a second and would be difficult to capture with a camera or in a screen grab.

Its not really a single square, its a set of neighboring squares so it kinds of looks like a Minecraft structure. It not necessarily aligned to the edge of anything either so it could appear anywhere in the screen.

My research so far has pointed me towards the graphics card except I ran diagnostics and it said everything was good.

What can I do to uncover the cause or stop it from happening?

 

[poked]

Sounds like dead pixels related to a graphics card. I have some in my 2013 Air, as well, at the very bottom of the screen. I’d say take it to a Genius Bar/Apple store and see what they tell you. Or your loc Best Buy if you don’t want to fork over a lot of money for the same graphical card dead pixel information. Do you have an external display you can test it on to make sure it’s the gfx?

 

[jstifcio]

Its not a bad pixels, its probably GPU issues. I've got the same problem with my iMac 27 2019 with 575X I have red squares while im using quick look, working on Lightroom, FCPX and even Safari. Reinstalling hasn't solved that issue. My polish seller ignored it and after 3 times visiting their service they don't know how to help me so I decided to go to the court but now Apple is trying help me and they will be contacting with my seller and trying to solve the problem.

 

[poked]

Its not a bad pixels, its probably GPU issues. I've got the same problem with my iMac 27 2019 with 575X I have red squares while im using quick look, working on Lightroom, FCPX and even Safari. Reinstalling hasn't solved that issue. My polish seller ignored it and after 3 times visiting their service they don't know how to help me so I decided to go to the court but now Apple is trying help me and they will be contacting with my seller and trying to solve the problem.

Notice my statement: “dead pixels related to a graphics card”….

 

[BrianBaughn]

Notice my statement: “dead pixels related to a graphics card”….

Distant cousins, I presume.

 

[PinkyMacGodess]

Dead pixels are permanent, depending on background color. They usually don't just 'go away'. It sounds like, to me, the OP is experiencing artifacts of the change in video resolution, and/or content. I had a Windows box that would appear to have a seizure when the video resolution and/or content changed. It was annoying, but happened irregularly too. Occasionally worse, and some times not happening at all, but usually there was some artifact visible, for a split second. That card eventually died, and the replacement did not exhibit any artifacts at all (different brand). It could be driver issues, but seems to be mainly, IMO, hardware. On the iMac, you are largely stuck with what you get unless you can open it up and swap the card, but the range of replacement cards is limited. Good luck...

 

[henryaaron]

Dead pixels are permanent, depending on background color. They usually don't just 'go away'. It sounds like, to me, the OP is experiencing artifacts of the change in video resolution, and/or content. I had a Windows box that would appear to have a seizure when the video resolution and/or content changed. It was annoying, but happened irregularly too. Occasionally worse, and some times not happening at all, but usually there was some artifact visible, for a split second. That card eventually died, and the replacement did not exhibit any artifacts at all (different brand). It could be driver issues, but seems to be mainly, IMO, hardware. On the iMac, you are largely stuck with what you get unless you can open it up and swap the card, but the range of replacement cards is limited. Good luck...

I think you're on target except there's not usually an artifact. Generally, I don't think my graphics card should stumble on switching tabs in Safari. I'm leaning more on a driver issue but I don't want to spend all the time reinstalling MacOS...

 

[PinkyMacGodess]

I think you're on target except there's not usually an artifact. Generally, I don't think my graphics card should stumble on switching tabs in Safari. I'm leaning more on a driver issue but I don't want to spend all the time reinstalling MacOS...

That's tough, but driver issues and hardware issues can seem quite similar, in my experience. Weird stuff happens. I had a video card in an HP 'thin system', and it would freak out on occasion. It also eventually died, and I had to replace it. So before it died, was it hardware, or software, or some sick mix of the two. Since it always did that freakout when the resolution changed, was it always about to die? And how could a mere mortal tell? (Was it off-spec memory, not clearing on time? Was it a flaky processor that wasn't working as fast as it should? Was it a driver not processing things in the order they should be to not have screen artifacts?)

That HP 'blessed' card would 'stumble', it would show a quick flash of *something* when the rez changed. I guess that's all I can add. Good luck...