MacBook Pro M1 external screen flickering

A couple of days ago I got my new MacBook Pro 14" and also got a new BENQ PD2725U external monitor as this is all replacing an old iMac. I have a very serious and very specific screen flickering issue that is especially apparent when running "Dark" appearance. The flickering will start after a few minutes and I can specifically force it by placing a window on the screen and moving it around the screen for a few minutes or displaying dark moving content/scrolling dark content.


For anyone that comes across this same issue I've managed to do some further testing and have some conclusions. Note I have a case open with Apple and hope they'll take the issue seriously. I may need to consider returning the laptop and the screen. It may even force me to a Windows laptop (at least for a while) since I can't get a new Intel MacBook Pro

For reference I ruled these out previously:

1. Cable/ports - I'm able to get the flicker to occur on Thunderbolt and HDMI as well as trying multiple thunderbolt ports
2. Power - I've tried different power cables and different sockets around the house
3. Refresh rate - Happens at 60 and 30hz
4. Colour profiles/brightness settings etc - I've ruled all of these out

To test out I've used 3 different laptops on the same monitor. These are:

1. MacBook Pro 14" (10 CPU/16 GPU) M1 Pro running Monterey
2. MacBook Air 13" M1 2020 running Big Sur
3. MacBook Pro 15" Core i7 (Radeon Pro 555 2GB) running Big Sur
4. Monitor is the BENQ PD2725U Pro Designer monitor

The test:

In each case I used the same Thunderbolt cable and same monitor. All machines are set to "Dark" appearance and have the same background image to give a fair test

Test 1: MacBook Pro 14" (1) - After around 5 minutes displaying dark content flickering starts to appear. Moving the window around to different locations changes the flickering/ghosting that appears

Test 2: MacBook Air 13" (2) - After around 2 minutes displaying dark content flicking starts to appear. Moving the window around to different locations changes the flickering/ghosting that appears

Test 3: MacBook Pro 15" i7 (3) - I cannot make the screen flicker no matter how hard I try!!!

Results:

1. Issue is present on both M1 machines
2. Issue is NOT present on the intel powered MacBook Pro 15"
3. Issue is present on both Big Sur and Monterey when on M1 processor

Conclusions:

1. M1 GPU has an issue with external displays OR
2. Some external displays have a compatibility issue with M1 GPU
3. My display is faulty but it is only being presented when connected to a machine with M1 GPU

Huh so it wasn't just me. I had recently returned my S3221QS thinking that the flickering was due to the faulty monitor but my new Samsung monitor does the exact same thing again.

It's odd because the display works just fine when connected to Windows. I tried different cables, changed the settings around but still the same. Out of ideas now

I've seen this with my LG 4k monitor, it's some kind of bug related to night shift, try disabling that under display settings and see if it resolves the issue.

kha422 said:

Huh so it wasn't just me. I had recently returned my S3221QS thinking that the flickering was due to the faulty monitor but my new Samsung monitor does the exact same thing again.

It's odd because the display works just fine when connected to Windows. I tried different cables, changed the settings around but still the same. Out of ideas now

Hey, please raise with Apple support. Hopefully it is just a software bug but we need apple to know how widespread it is.

I haven’t for any real length of time ran in light appearance. I’m going to try that. It’s a workaround at least for now though I believe it could still present itself if watching moving dark content like a movie

Ron21 said:

I've seen this with my LG 4k monitor, it's some kind of bug related to night shift, try disabling that under display settings and see if it resolves the issue.

I don’t have night shift enabled but I might try flicking it back and forward. So far it appears related to dark content so easy to reproduce using dark appearance mode.

Does your 4K monitor have a IPS or LED screen? I've read that this issue doesn't happen on IPS monitors.

infernoguy said:

Does your 4K monitor have a IPS or LED screen? I've read that this issue doesn't happen on IPS monitors.

The monitor is an IPS panel. More details of my monitor that is impacted here https://www.benq.eu/en-uk/monitor/designer/pd2725u/specifications.html

I've had other users tell me its also happened on an Asus and also an Acer.

It appears to be related to things changing on the screen when there is dark contact. I also think there is some effect in light mode with light background but its much less apparent so the workaround is to use light appearance and lighter backgrounds. I'd much prefer to be running in "Dark" appearance however that is pretty much unusable

Same issue here, I use Xiaomi 27" Monitor RMMNT27NF in my MacBook Pro M1 2020 with Monterey OS, and I still see this issue in MacBook Pro Intel 2020 (Monterey OS) with same Monitor. But, i don't see this issue in Windows. So my assumption it's OS or Driver issue.

Hope Apple fix this issue.

Hi all

I've been chatting a lot with apple support but 2 things have happened, 1 of which you could try...

1. On Reddit someone mentioned installing CleanMyMac resolves the issue. No idea or why or if it definitely does, but after installing on mine and a restart I've not seen the issue happen again... however see below as this could be a red herring

2. I had another, seemingly unrelated issue with the BENQ. BENQ support decided they wanted to RMA it but unfortunately there was no stock at that time and I didn't want to be without a monitor. So I switched monitor to EIZO CS2740 instead. The issue has never appeared on this monitor

So at the moment I'd say one of three things happened. Either CleanMyMac did indeed solve the issue. I'm sceptical of this but you never know. Or there was a monitor issue that was intermittent (seems more likely but doesn't explain that others have exactly the same issue with different monitors). Or there is a compatibility issue between M1 and some monitors.

I'll update if it happens again on the new monitor but a few days in and it appears fine

EvilHomer80 said:

Hi all

I've been chatting a lot with apple support but 2 things have happened, 1 of which you could try...

1. On Reddit someone mentioned installing CleanMyMac resolves the issue. No idea or why or if it definitely does, but after installing on mine and a restart I've not seen the issue happen again... however see below as this could be a red herring

2. I had another, seemingly unrelated issue with the BENQ. BENQ support decided they wanted to RMA it but unfortunately there was no stock at that time and I didn't want to be without a monitor. So I switched monitor to EIZO CS2740 instead. The issue has never appeared on this monitor

So at the moment I'd say one of three things happened. Either CleanMyMac did indeed solve the issue. I'm sceptical of this but you never know. Or there was a monitor issue that was intermittent (seems more likely but doesn't explain that others have exactly the same issue with different monitors). Or there is a compatibility issue between M1 and some monitors.

I'll update if it happens again on the new monitor but a few days in and it appears fine

Click to expand...

How would CleanMyMac fix it?

infernoguy said:

How would CleanMyMac fix it?

Literally no idea, I think it is probably a red herring and didn't actually change anything, but I can't really explain the events that happened after. As someone had mentioned it on reddit and I already have a license for it anyway, I thought I'll throw it on since it didn't hurt.

I put it on, then a day later I had a support call with Apple and tried to reproduce the issue. I wasn't able to do it any longer on the MacBook Pro 14 with CleanMyMac installed. I then put the MacBook Air M1 (no CleanMyMac) back into the monitor, same cable, and tried to repeat and within 5 minutes flickering started again.

I wouldn't recommend rushing it out and buying it unless you want the features, I think there was something going on with the monitor, but sharing what has happened so far

MacBook Pro M1 using external screen Acer CB281HK 4k model. Using white (not dark) mode, external monitor flickering. reproducible by loading up system ie multiple programs or many tabs on safari. Even in minimal work mode that an old intel MSI could do, new machine was failing. It almost looked like an interlacing failure on some images / screens.

Possible solution: changed built in display to 60Hz (from ProMotion). Access via settings > Displays > displays > refresh rate. (note: fault on external display, but fix seems is applied on built in display!)
Good luck, as my first apple laptop, was NOT happy with this fault.

This seems to have been fixed for me with 12.1.

jerryitall said:

This seems to have been fixed for me with 12.1.

It will be interesting to know if it worked for others. I wasn't able to reproduce in the end after the monitor change.

jerryitall said:

This seems to have been fixed for me with 12.1.

I still have this issue even i updated it to Monterey 12.1 My external monitor is Xiaomi RMMNT27NF. What i should do?

I had the exact same issue with my 2021 MacBook Pro (M1 Pro) & Dell 4K S2722QC.
Had Dell offered a replacement but didn't help.
Eventually tried the turning off "nightshift", "True Tone" and "Automatically adjust brightness" and it worked for me.

I tried my brand new MacBook Pro M1 Max with MacOs 12.1 on two displays. On my Asus MG28U (4k), the resolution is fine, but after some time, flickering occurs, and vertical stripes appear. I tried all Thunderbolt ports, the HDMI port, and different cables, but nothing solved the issue. On my colleague's LG 35WN73A (ultra-wide 5k), the resolution is bad. It doesn't look 4k at all. Instead, I can see the pixels in the text...

The issues that M1 MacBooks have with ultra-wide displays have been known since at least the end of 2020, and Apple officially acknowledged them. So it is very disappointing to see that they are still not fixed.

I was able to reproduce the flickering issue and the stripes on the Asus MG28U. It appears to happen when it gets darker, and I turn on the light on my desk. Plus, True Tone and "Automatically adjust brightness" need to be activated for the internal display. The moment I turn on the light, the flickering starts, and the stripes appear. When I turn True Tone off, it disappears.

I was also able to get rid of the stripes and the flickering when activating the color profile "sRGB IEC61966-2.1 for the external display. The whole issue becomes much more apparent when looking at dark backgrounds.

Issue is still not fixed in 12.1, when night shifts enables, my monitor will start flickering shortly after that. Disabling night shift resolves the issue right away on my end.

No fix here with 12.1. I downgraded to Big Sur and flickering issue is gone and my MX3 mouse back/forward buttons is working as it should again. Im going to stay here until Apple fix it.

Mac Mini M1
Benq PD3220U

We bought a number of 16inch MacBook Max laptops and all flicker with specific monitors. We have a dozen LG 32UN500-W that will flicker with vertical lines and some BENQ that do as well but not sure on model. We have a dozen LG 32UD60-B that don't flicker.

We have also tried a bunch of different usb-c to hdmi and usb-c to display port all with same results. All these cables were used with previous generation MacBooks with no issues. In any case, we bought different brands of cables to rule out cables.

We tried every possible setting on the monitors with no help. By turning off Night Shift, True Tone, changed the color profile on the external displays to Color LCD and it seems to help reduce the issue. Also, we enabled HDR for the external monitors in Monterey and it helped substantially but we believe its due to how the darks are significantly less dark in HDR mode and that is when we see the most vertical lines and flickering. Personally, none of us like the way things look with HDR enabled in MacOS but some are using it to avoid the flicker for now.

In last ditch effort a couple of us installed Monterey 12.2 BETA and same issues exist.

Everything else about these laptops is fantastic but this is pretty ridiculous especially after all the issues with the Intel 16inch MBP's (heat, fan, and internal and external display issues). Apple needs to get its stuff together.

This is making me want to keep my dual 1080p screen setup. Yeah the text is grainy but I can live with that instead of the flickering.

had similar very annoying flickering issues with a Dell S2722QC for days [drove me bonkers], then I took a few steps [listed below] which did resolve the matter [steps 1&2 seemed to be the culprits, the Thunderbolt hub is just extra protection for my macbook pro 14" & my peace of mind as I trust that much more for power/data/display delivery than the monitors own hardware;

1. prioritized image quality over data quality in options in Dell on-screen menus
2. turned OFF all PD [power delivery] while sleeping or off options in Dell on-screen menus
3. added a powered thunderbolt hub between macbook and screen via USB-C which includes PD


and have had ZERO flickering ever since...


PS: make sure refresh rate is not defaulting to variable rate and that true tone and any other silly bugger screen crap is also OFF>

In my case, the culprit was the refresh rate set as "variable rate" on my external Samsung monitor (new MBP M1 Pro 14"). I also had color issues with TrueTone on.

I'm having lots of issues with my BenQ PD2700u. at first the display was flickering and becoming completely corrupted after short periods of use. I isolated the issue to trying to use the app 'monitor control' to adjust brightness without having to fiddle with the display's OSD. apparently despite the app saying apple silicon support, apple silicon does not work with DCC. disappointing.

further, just having a display connected tanks the computer responsiveness substantially, which is very disappointing on an m1 max with 32 gpu cores.