Mac Mini (M1) 2020, LG UHD monitor flickers on dark colours.

I changed the update frequenzy in the settings. Solved everything for me.

My Benq had exactly the same issue. Benq sent me a new one thinking it was monitor related but same thing again. Flickering.....

I think it's not monitor related, it's an issue with the mini M1.

Just an observation I've had, that maybe somebody else can test,

Ive set the black levels to high. and my monitor hasn't flickered all day, just wondering if anyone else has tried anything like this. (the picture definitely looks better with black level set to low, but I'm wondering if this is the issue)

Hi -

I just wanted to say that I've got the EXACT SAME ISSUE.... Brand-new Mac Mini M1 with 2 x Samsung U32R59x 4k 32" Curved displays. One is connected via HDMI and the other via DP via a CalDigit TS3+ dock. Most of the time, both of the displays are working fine at their full resolution (3840x2160), but whenever there's a scene that's fading from black to white or vise versa or when watching movies (especially full screen), it flickers like crazy. When it's "flickering", there's very fine vertical grey and green lines.

It's definitely not the monitors as I've gone through 3 of them now (Amazon was more than happy to send replacements). Also, it's the same when using HDMI or DisplayPort (DP) via a dock. I've also got expensive $50+ HDMI and DP cables in-place. The change to the expensive cables did not improve the issue. Unfortunately I haven't been able to find any solutions or work-arounds... I've tried different resolutions, different colour profiles and tweaked all of the settings on the menus of each monitor -- to no avail. This is definitely an issue with the Mac Mini 100% as this issue is not reproducible on a Windows-based machine. Hopefully Apple releases a patch soon, but I'm glad it's a "common" issue as I was starting to go crazy!

I have switched my monitor from the LG 32UN500-W with LG 27UL550-W monitor and no longer getting the flickering issue. Im not sure if its because I switched from a VA to IPS panel monitor or that every monitor is different.

Just so everyone knows, this issue is NOT limited to the HDMI port on the Mac Mini... I've got a CalDigit TS3+ dock and the SAME issue occurs over the DisplayPort connection as well. It seems to be an issue with the GPU (M1 chip) or some sort of software/processing/filtering that's going on in MacOS.

Considering how widespread this issue is now, I'm shocked that Apple hasn't either released a fix or statement on the issue... I can't imagine there's too many people out there successfully editing/viewing video with a non-Apple 4K display on these machines, as they'd surely be experiencing this flickering / fine lines.

I sold my S3221QS to my brother (he uses a Windows device) and bought a BenQ EW3270U and I've been flicker-free so far.

Dell did admit to me in an e-mail that the S3221QS isn't compatible with the M1 Mini, which leads me to believe it's more of a manufacturer issue. Still frustrating though.

From an e-mail received by Dell (I didn't buy one of the parts to try their fix, as I don't think there's a guarantee that fixes it and didn't want to dump more money into the monitor):

Upon further checking with our support specialists, the issue is confirmed to be a compatibility issue and the only resolution provided is to use any of the following adapters

• Dell USB-C to HDMI Adapter (Dell Part #47KD7)
• Dell USB-C Mobile Adapter - DA310 (Dell Part #0XJD9N)

What has worked for me is to reduce the native resolution of the monitor to 2560 x 1440, I no longer have 4k res but at least I can work without flickering. BenQ el2870u, hdmi - hdmi Ugreen 2.1 Cable 8k / 60Hz.

Yes I agree def with Mac mini but it seems to have a compatibility issue with some monitors - for me it was just easier to replace the monitor as there is not alternative to the M1 mini that suits my needs.

Same problem here on M1 Mac mini and M1 Air. Tried thunderbolt > HDMI cable, $100 HDMI 4K60 cable with the same result.

Also noticed that the problem occurs more often with darker backgrounds and in dark mode.

In my case I'm using Samsung U32R59 monitor.

Definitely a software/driver issue - color profile change in most cases fixes the issue, but not permanently, as is different profiles have this glitch in different situations.

macOS 11.5.2

Resolution: 5120x2880 (5K/UHD+ - Ultra High Definition Plus)

UI Looks like: 2560 x 1440 @ 60.00Hz

P.S. Scaling change also doesn't help.

Gengar, Turning on HDR does fix the issue.. but it might have washed out colors. I have the same issue and turning on HDR from Display preferences fixed it. Id recommend downloading the ICC Color profile to get your HDR colors back

I too have an Asus VP28UQG 4K monitor. Supplied cable from Asus, I had ghosting and the vertical lines randomly. I upgraded to an HDMI cable that can handle 8K video to see if the additional bandwidth capabilities would eliminate the issue as others had mentioned. Issue still present but not nearly as much or as bad. Tried USB-C to DisplayPort and that produced no change and very similar to the supplied cable from Asus. I tried the display settings set to Display P3 and while initially appeared better, the issue eventually crops back up. Will be trying other settings with macOS Monterey, resetting of the monitor, but outside of that it would be nice if Apple would acknowledge and fix the issue.

Yep, still a problem for me with my Dell 3221QS UHD monitor. It is better with the display and Mac in P3 colour space but it does still happen. I've found HDMI is a lot better than DisplayPort and having the monitor in RGB mode also improves things but the issue is still there. Having most of the screen dark grey or black seems to trigger it more than brighter colours.

just wanted to Provide an update for my issue: am in contact with apple rep at the moment, (good idea to buy apple care for frontier hardware). We went through the whole diagnostic run and still have no solid solution, but my rep has expedited the complaint to engineers and we are meeting again in another day or so.

What I have been able to achieve is a compromised workaround. I am using the 60hz setting on my display (LG 34 WL500-B) and the color prof "ColorMatch RGB". This paired with the no night shift, and no sleep/ energy saver mode tricks and some small tweaks in the monitor's hardware settings has gotten ride of the majority of the problem for now. I do my best to avoid the extreme color situations that seem to trigger the issue( brought yellow gradients, dark reds and large solid patches of green) and things are mostly ok for now. of course, this color profile is not ideal for color accurate work so I'll continue to dig for some more fixes. I'm going to try and switch from an HDMI>HDMI connection to a USB-C>HDMI cable and see if that changes anything.

I'll be sure to update here if anything changes!

My screen has not flickered since I installed the 11.2.3. update. Fingers crossed!