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

Same monitor (LG 32UN500-W), same Mac mini M1. Tested two different cables (glitches persists). Big Sur sometimes reports the monitor as 5k (?). Also tested the same monitor + same cable + MacBook 15 (mid-2014) = everything ok. Same Mac mini M1 + same cable + LG TV 4k HDR (MY 2019) = everything ok. So it's not a monitor, cable problem. It's a Mac mini M1 + Big Sur problem. Looking forward to Apple producing correct driver soon.

It's present in 11.0.1 and on 11.1 public beta (v. 1) which I am currently on.

i also had the same issue from the usb c to DisplayPort

try adjusting the sharpness settings on the monitor within picture on the menu , increase or decrease as crazy as it sounds , no flicker so far since doing that.

and agree , it’s disgusting they are ignoring the issue . I think it’s because it’s hardware related and no software update will fix it

I made a video with comments. So have look please:

https://youtu.be/oK6-UEs60so

Degrading to Display Port 1.1 helps but not in all cases. Changing color temperature helps but not in all cases. Changing gama to 2.0 helps but not in all cases. Toying with contrast helps but not in all cases Changing monitor color profile in system settings helps but not in all cases....

Changing scene a little (adding a highlight or moving a window on the desktop) helps 100%

There are two occasions:

1) everything is flickering except the movie being played

2) all screen is flickering

There are also vertical lines visible with bare eye (my phone just couldn't capture them)

Is it some kind of timing problem??? large area filled with many shades of dark grey feels like the trigger. It looks like sync problem (phase shifting) as if you use analog input on LCD panel.

STRANGE!!!!!!!!

I have the Dell S2721QS and right now have been flicker free for about a month (fingers crossed). I'm using a 3ft Zeskit Maya HDMI 2.1 cable, I also switched HDMI inputs to HDMI 2 (Problem for me happened a lot more often on HDMI 1 for some reason), this had solved the problem 90%. The other 10 percent seems to be taken care of after calibrating a color profile and using that. It seems you've done most of these things, but try using HDMI 2 and perhaps a shorter HDMI 2.1 cable like I did. Obviously, we shouldn't be needing to do any of these things, but hope this helps.

I have the same monitor, and a 2016 Macbook Pro 13 inch.

My experience is by changing the response time from normal to fast or extreme will eliminate the edge flickering when scrolling dark background sites for example I get guaranteed vertical flicker lines when scrolling on Youtube in dark mode.

However when watching videos I still notice some frame, not essentially dark, will cause the flicker, if I paused at the right time it will keep flickering, while the previous or later frame is almost the same image.

I have no issue with the monitor when connecting to game consoles.

if all those monitors work with other hardware flawlessly (which they do) both old macs and pcs it is not the monitor that is the problem it is the M1 chip itself. No standards have been changed and the M1 should be compatible with all monitors.

the best thing that can be done is a list compiled of working monitors or a recall on the entire M1 lineup especially the Mac mini which it affects the most since there is no internal screen.

I ended up returning the Benq for 2x LG UL550 not had a problem since for a few months now. Only issue Is if I don’t wake the screen manually before the Mac mini it forgets its resolution.

has anyone noticed that in system report the Mac mini is actually outputting 5k to a 4K screen ? I wonder if the scaling is an issue since the monitor is working hard downscaling.

The display port makes no difference, you will find the flickering will start on different shades of dark grey to the shades of grey that triggered the flickering on the HDMI. I had a BENQ EL2870U and tried all sorts for a month. In the end I swapped it out for a LG UL550W far more expensive but no issues since. This does not mean there was anything wrong with the BENQ , this is a compatibility issue with apple rushing to market the M1 and the standards have not been checked. Something has been missed somewhere.

Has anyone else noticed though that in about this Mac > system report > graphics displays > Resolution when a 4K monitor is connected is listed as 5120 x 2880 which is 5K? This means that the monitors are doing all the work downscaling to 4k. I remember when I had it set on 2k the flickering issue went on the benq. I think this has something to do with the problem there is no setting for 4K scaled output which looks like 2560 x 1440.

I have the same issue on M1 mini and Dell 4K. One dell is 27" and other one is 24", both 4K. The one has TB-DP connection and work flawlessly (this is 27"), the other is connected HDMI-HDMI (24") which has vertical lines flickering and picture disappearing for few seconds, which is very annoying.

I'm slowly considering asking official retail for replacement of M1, but this might not solve the problem at all. Main issue is that macs have only 1 year of warranty and this may expire before we will know if there will be any fix or not.

One thing I have found out that temporary helps is unplugging HDMI from mini and plugging it back. This will make monitor flicker free for few minutes. Also putting mac to sleep seems to worsen the problem, so it might be something wrong with sleep or display sync. Not sure as I do not have much time to dive deeper on this - this should be solved by Apple anyway.

Also if I go into system report I have this

 Displays:

DELL P2715Q:

  Resolution: 6016 x 3384

  UI Looks like: 3008 x 1692 @ 60.00Hz

  Main Display: Yes

  Mirror: Off

  Online: Yes

  Rotation: Supported

  Automatically Adjust Brightness: Yes

DELL P2415Q:

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

  UI Looks like: 2560 x 1440 @ 60.00Hz

  Mirror: Off

  Online: Yes

  Rotation: Supported

  Automatically Adjust Brightness: Yes

I would say a problem might be too high resolution set on HDMI as it doesn't have enough bandwidth to display it anyway.

Replying to myself here, because I realized that what causes the problem to go away, is actually some combination of parameters. Using a preset color profile (reddish) that shows the problem here, the problem disappears when raising the contrast above 48. So you may need to try a few things to make it work. Good luck. :)

Hi All,

I have two Benq 4k monitors connected. One by display port and one by hdmi. I used to get shimmering and flickering and random lines etc etc as many of you are experiencing. I appear to be one of the lucky ones that have completely eliminated the issue. See the settings on the attached screenshot. To be clear - these settings work on my duel benq el2870u 4k displays. Hope this helps some of you. Key to the fix is enabling HDR. If I switch it off, the flickering comes back. Oh yes, just remembered. I have also disabled night-shift!!

I am using LG 32UL500 monitor with M1 mini and was getting frequent screen black (like off-on). I tried many of the suggestions in this thread but the only thing that worked for me is changing the refresh rate to 30Hz. This makes the screen feel slow, especially mousing around, but it is much less annoying.

Can you confirm whether or not the ‘black level’ on the monitor is set to ‘low’ or ‘high’?

ive had no flickering since I set it to high.

I can reproduce the issue (vertical stripes and flickering) with a specific youtube video in safari. But, if I play the same video within a videoplayer (elmedia player), the issue doesn’t occur…

I had the same issue with a Viotek gaming monitor I bought a HDMI to USB-C adapter and it resolved it for me

Hi, I had this problem using a 4K TV as a monitor, I tried to change the HDMI protocol on the TV from 2.0 to 1.4 and it solved the problem. So my guess is that high quality cables are essential.