MacBook Pro 16'' with M1 pro flickering with my 4k BenQ EW3270U USB-C monitor with display refresh rate at 60 Hertz

My old MacBook Pro (2017) had no problem with the same display. It uses a USB-C connection.


When I set the "Refresh Rate" to 60Hz I see a terrible flickering at all resolutions (see https://youtu.be/1QrWnhTF6yU). If I set it to "Variable 40-60 Hertz", the flicker is gone, but big dark areas flicker (I cannot capture that by video).


If I run it at 30Hz it is terribly unresponsive.


To make things worse: every time the display wakes up it resets the refresh rate to 60 Hertz



Posted on Oct 30, 2021 12:20 PM

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Mar 1, 2022 7:00 PM in response to geek_42


I’m having this issue. I’musing my Xiaomi Mi 27 inch external monitor using HDMI and I experienced flickering and linear lines. But on my MB 2019 16” i9, I don’t problem with it. Only on my M1 Max. I think the problem is the GPU of M1 chips. Apple needs to fix this issue.

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Oct 31, 2021 1:35 PM in response to geek_42

Hello geek_42,


Thanks for reaching out through the Apple Support Communities about that behavior when using your external monitor with your new MacBook Pro.


Have you had the opportunity to test your new MacBook Pro with any other external monitors?


How about testing with another USB-C cable?


Does this occur with all the Thunderbolt 4 ports on your new MacBook Pro?


Hopefully those details will help to further isolate this behavior.


Take care.

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Oct 31, 2021 3:15 PM in response to chuckbl

Hello chuckbl,


I tried different usb-c cables and different ports without getting any different results. I tried with HDMI but the cable I have does not support 4k at 60 Hertz. Unfortunately, I don't have another 4k Monitor to test it....


I also tried to boot the computer in restricted mode with the same result.


The only thing that helps is to set the Refresh rate to "40-60 Hertz" which solves the problem and the monitor claims it is running at 60 Hertz. So everything would be good, but each time the display is turned off, the refresh rate is reset to 60 Hertz which causes the flickering...


Michael

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Nov 16, 2021 6:28 PM in response to majortom1967

Exactly the same is happening to me with my BenQ Monitor but the model EW2780, but is intermittent, sometimes start flickering and creates ghost images, I restart and flickering go, few hours and start again. But there are days that everything is good. The problem start just after the update to Monterey. I try using HDMI but didn't work. And this is happening to me with my Mac mini.

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Nov 30, 2021 10:00 AM in response to chuckbl

Experiencing the same issue with a Gigabyte M32Q USB-c monitor and MacBook Pro Max 16-inch. Flickering only occurs when connected via USB-C. HDMI connection is flicker free. I’ve used two different brands of cables so far with similar outcomes. Also experienced the flicker issue utilizing different Thunderbolt ports on the MacBook.

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Dec 7, 2021 7:46 AM in response to geek_42

Just to say I also fixed this problem by using an HDMI cable rather than the USB-C to DisplayPort cable.


I'm using a Dell S2721QS external display (capable of 4K at 60hz). I just got a new M1 Mac, running macOS Monterey and experienced this flickering problem for the first time. I was on a 2013 Intel MacBook Pro before, running Big Sur and never had this problem when connecting the display.

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Dec 13, 2021 2:22 AM in response to geek_42

I have a MacBook Pro M1 Pro 14-inch and a similar issue (flickering) on a Dell U2720QM using the USB-C cable that the screen came with. I had no issue with my previous MacBook Pro 13-inch (2018)... I hope that a software update can fix this annoying issue.

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Dec 13, 2021 2:50 PM in response to geek_42

I am also facing the same problem with Macbook Air M1 on Monterey.


The screen supports 4k @ 60 hz through usb-c -> DisplayPort. I had this setup for over a year with different macbooks on Bigsur and below and never had any issues. Only with the Macbook on Monterey.


It doesn't flicker, but the screen goes blank for a second or two and comes back when it's on 60hz. I am using Dell S2721QS

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Dec 21, 2021 4:57 AM in response to geek_42

We purchased a handful of 16inch and 14inch M1 MBP's. We have been pairing them with three different 4k monitors. HP, LG non HDR, LG HDR. The HP and LG non HDR have very little flicker or vertical lines but the LG HDR has been a mess. Keep in mind, we had previous generation MBP's connected with all the same cables and monitors with no issues and many of us also have Windows laptops or desktops for different kinds connected to these same monitors / different inputs with no issues.


The LG HDR monitors flicker like crazy unless we turn HDR in Display Settings on the MBP for the external display. As soon as we do that, no flicker from the MBP's with the LG HDR monitors.


We have tried MANY different USB-C to Display and USB-C to HDMI all with the same results. HDMI to HDMI we haven't seen the issue but we also have been focused on USB-C cables since we had so many from our 2020 Macbook's and all our employees use dual monitors in addition to the laptop screens.


I'm old school and play Startcraft 2 on the M1 MBP. When playing on the LG HDR external display without HDR enabled Starcraft flickers allot and it has the vertical lines. Certain menus within the game cause it as well. In Monterey, when we move windows around or off the screen we can reproduce the same issues. The problem seems to be lighting, shading or certain textures.


Fortunately with so much equipment to test dozens of scenarios were able to find some solutions but Apple really needs to fix this. We have seen no improvements change display rates or monitor settings or factory resetting monitors etc. We really tired everything!


Hope this helps others who are seeing issues. Other than the external screen problems the new MBP's have been fantastic in every other way.


Tim

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Dec 21, 2021 5:06 PM in response to geek_42

I have a similar problem on a MBP M1 Max, not exactly a flickering, but when I use my USB-C -> Displayport cable on the thunderbolt right above the magsafe, I just get a black screen (System > Displays) shows my monitor but no image is displayed.


If I change to the second left thunderbolt port it works with no problem, same with the right thunderbolt port.


To be clear, all thunderbolt ports work for charging and external devices, it's just for the external monitor that I'm having this issue with the first thunderbolt port from the left.

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Dec 25, 2021 1:14 AM in response to geek_42

Have the same issue with my Macbook Air M1 -> CalDigit TS3 -> Dell S2721QS. Variable refresh rate in MacOS work on 40hz and not flicker but some software like chrome with youtube fullscreen mode or telegram with full screen photo preview made 60hz and flickering return. Tryed YPbPr instead RGB it help. I can work in 4k60hz but I don't know how force YPbPr, MacOS and monitor return to RGB after lock screen.

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Dec 25, 2021 1:58 AM in response to geek_42

Found some solution for dell s2721qs. Turn on monitor smart hdr in desktop mode, turn on on mac hdr in settings then turn off. Now I have stable 4k60hz rgb with turn off hdr on mac. Don't know how long it will be work, tried lock screen work fine after. Also turn on fast wake up on my monitor.

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MacBook Pro 16'' with M1 pro flickering with my 4k BenQ EW3270U USB-C monitor with display refresh rate at 60 Hertz

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