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

I`ve got feeling it has something to do with timing and synchronization. If you set colour space to some wider kind (esp. SMPTE RP 431-2-2007 DCI (P3)) Monitor works almost flawless. If you encounter this flaw again, setting monitor sharpness to 0 helps again. If flaw still persist then manually degrading DP to 1.1 version helps again (you can choose between 1.1 and 1.2 on Philips monitor). Also setting monitor colour temperature from 6500 K to sRGB colour space helps again. Now I have eliminated the flickering vertical lines flaw in 99% of time. It occurs again if I try to lay some old lo-fi dark, lo FP, low resolution videos on Youtube. To me it feels like display is losing sync while colours are too dark. What about colour bit depth? How many bits per pixel is the graphic card vs the LCD panel? Those shivering vertical lines remind me of setting the trigger level bad on an oscilloscope. It feels to me like monitor cannot guess beginning of line. Most interesting is that downscaling or overscanning eliminates this problem 100% (set on monitor itself, not in system settings panel). So again!!! Dose monitor lose sync while there are large areas displayed in same bit depth on monitor while meant to be in different bit depths by the graphic card (using wider colour space helps)?

FWIW, I switched to a new USB-C — DP cable and, so far, it's been working fine for 24 hours. Naturally, as soon as I hit "Post" it will start going nuts again and flickering out to black every couple of minutes but for now it's working as expected.

I'm having the same issue. I also bought a USB-C - DP cable. While it solves this particular issue (grey vertical lines and sometimes ghosting if left unchecked), it also creates a new one. Sometimes, after waking up the Mini from sleep, the monitor is showing pink lines in the upper part of the screen. I need to turn it off and on again to get it to work. Still, it's much better than the issues I've been having via HDMI and USB-HDMI cables.

What's most annoying, is that I had literally zero issues in the past, and I've been using my monitor with a Windows laptop, PS5, Series X and now the Mini. For all other devices except the Mini it works flawlessly, so I am seriously disappointed how Apple is handling things here.

I regret not returning the Mini while I still had the chance. I didn't do it because it felt like an obvious quick kill on Apple's side, especially considering how impactful this is and how many people report issues with external displays.

I have to correct what I wrote yesterday. I retried the DP cable and after rebooting it seems to work much better with the DP cable than with HDMI. Only very light vertical lines. After setting the monitor from DP1.2 to DP1.1 it seems to be fixed for the moment and I can not see any issues right now.

So... just updated to 11.2.2 and the problem still exists, maybe even worse now. My second monitor (Samsung R32R59x connected via DP through a CalDigit TS3+) just kept flashing and trying to "sync" this morning when I turned the computer on after fresh installation of the update. It took a few moments of it "flashing" off and on before it started working again. First time this has happened to me... normally it was just the "flickering" issue as described by the original poster. it's quite amazing that these M1-based machines are having so much trouble with 4K Monitor support!!

Got the same issue with an older Acer 24" FullHD display. Switched from HDMI to DVI input (via HDMI-to-DVI cable) - issue is still there, but the exact colors at which the flicker happens changed a bit.

Hooked up the Mini to my Samsung TV, couldn't find any issues there, not even the vertical lines in certain tones of grey.

A quick check with a friend's Philips 245E1S/00 didn't show any flicker, either, but I'd have to give it another try to be sure.

Hi all,

same problem here with mac mini m1 and BenQ PD2700U with display-port (the problem isn't the monitor)

The problem starts only if OS is in dark mode. BigSur 11.2.3 (20D91) and previous versions

Tried to connect and disconnect but nothing. The only solution is to put in light mode.

Softwares in dark mode don't cause flickering issue.

Yes, sadly I agree... it's really starting to look like it's some sort of hardware-related issue. Any it's not specific to HDMI and DisplayPort is equally affected. Maybe something weird going on at a silicon-level in the M1 processor/GPU?

Maybe they want to quietly put at a new hardware revision where this issue is fixed.

You'd think that four months should be enough to come up with a software fix, if possible.

But it seems sending in your machine for a repair or replacement right now is pointless.

Btw, im using a borrowed BenQ G2420HDBL FullHD display at the moment, this one seems flicker-free.

Yep, let's just say it as it is: the way Apple is handling this is disgraceful. They barely are aknowledging the issue, meanwhile this thread is exploding.

My guess is that the hardware is messed up in its core and no software update will save us.

I'd love to be proved wrong but it appears Apple doesn't give a **** about its customers so I don't see why they would show up and try to help.

I won't be buying from these crooks again.

I have a Dell 27" S2721QS and am having the same flickering happening, I can't trigger it at will, but it's happening mainly when browsing websites with many pictures/autoplay videos. The effect takes up to 5 minutes to wear off after I close the app that triggers the flickering. I am not getting any definitive answers on whether or not this is a software or hardware issue and I don't wanna be stuck with a dud so will likely return the M1 Mac Mini since I'm still in the return window. I have tried different lengths/types of HDMI cables, nothing fixes it and I only have the problem with the Mac Mini, so it's either the HDMI port itself or the brains behind it. It's a shame that I have to return it for this as I was really liking the Mac.

Maybe yours is a different issue? I have created an image filled with a "problematic" color and I can 100% reproduce the issue by opening it - but it's only the window the display the image that flickers.

So far it's only dark/grey colors that flicker.

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!!!!!!!!

Here's a little test I just did:

Create an image with a fill layer in Photoshop. Then play a little with the color picker, towards the dark grey end of the color space - I bet you'll find that some colors display flickering, some weird patterns or both.

Couldn't get any flicker with the BenQ monitor, but patterns in colors which should be solid.

I have the same problem!!! vertical lines and flickering issue, is very annoying!!!

https://youtu.be/Rk8K-6uVtNI

Moshi USB-C to DisplayPort Cable;

4K 60;

BENQ EL2870U;

Mac mini M1 8GB 256 SSD, Big Sur 11.2.3 Safe Mode

Tried HDMI same result.