I made a previous post about having severe issues with my previously usable intel iMac 2019 4K Retina running an AMD Radeon Pro 560X:

I’ve used the slo-mo 240fps test to check iPhones before - never on a desktop especially an old LCD like this. I did this test initially and saw flickering but assumed it was a normal artifact from the slow motion recording. After reading a ton of posts here trying to salvage this iMac, I realized that this is likely flicker, and probably the source of my discomfort. It is so bad that I can barely even look at the screen for more than a few seconds without getting a bad headache and trouble focusing my vision.

For context, I’m a music producer and engineer and I haven’t used this particular computer for 8 months. My previous post talks more about the health issues that seem to have led me to increased sensitivity, but I wonder if this screen or the graphics card is going bad. I’m desperate to save this computer because I frankly can’t afford to replace it, but I’m coming to the conclusion that I may have no other choice. I’m still pretty new to PWM and dithering as an issue so any advice/feedback would be so helpful.

video of flicker: https://streamable.com/rm605e

    AshX This is brutal, especially if you can pick it up with regular consumer video device. Have you tried writing directly to Apple and attaching this video ?

    • AshX replied to this.

        Donux I haven’t. Thanks for responding and confirming I’m not crazy. What’s concerning is I have no idea if this is recent or if I’ve been looking at this thing for 6 years 10+ hours a day. I only became aware of PWM/dither issues when I tried to upgrade my iPhone 13 to an iPhone 15 Pro and could not even look at the thing. Went down the rabbit hole and have been lurking these forums since ‘23.

        I had issues with this iMac 2 years ago but SwitchResX’s “millions of colors” option seemed to make it tolerable enough that I finished recording and mixing an album on it in 2023-2024. I kept having to stop using it and assumed it was long COVID related…maybe it was this. It was “fine” until I moved in 2023. It’s been sitting in its original box (protected with the molded styrofoam that it came in) in a storage unit for 8 months. Maybe the screen is on its way out? Backlight failing? Or is this a common occurrence with screens and I’m just sensitized to it now?

        May end up going to the Apple store and asking what they think…although I’m considering trading it in for the $200 credit so maybe that’s not a good idea lol…

          dev