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M1/M2 flickering, ghosting with external display [Merged]
- Thread starter aednichols
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M2Max MBP user here. Depending on the day, I run between 6 and 9 displays off the machine. Everything works perfectly, except for one issue. After about a week of uptime, my Dell 38" 3821DW, connected via HDMI, starts to lose sync and go black for a few seconds. The problem becomes more frequent over time, happening up to once every few minutes after 3+ weeks of uptime. Luckily, it goes away with a reboot.
My experience was specifically with HDMI (so different from you) but I have one piece of advice:
- The problem was connecting an M2 mac mini to an LG CX TV via HDMI<->HDMI cable. This gave terrible constantly flashing results. (Not the fault of the cable since I test the cable I use from my AppleTV to that same TV).
- I eventually resolved it by forcing the TV HDMI port from HDMI 2.0 down to HDMI 1.4. Seems like the Apple hardware can handle HDMI 2 (since aTV handles it fine) but the aTV driver team does not talk to the macOS driver team 😡🤬🤮!
- BUT the pointer I want to give you is that in the process of trying to deal with this I came across a piece of software called Better Display (the version I have, which I think is the latest, is 1.4.6)
This allows you to set up and control displays in a large variety of ways, most of which are details I do not understand (but you might)! The way I used it, which solved my problem, until I found the real solution of downgrading the TV's HDMI port, is as follows
+ use Better Display to create a FAKE (software only) display of the resolution that you want.
+ use the Displays control panel to force mirroring of that fake display onto your real hardware display.
You'd think this is basically doing nothing, but apparently this scheme forces the timing and various technical details to be copied from the Better Display and forced onto your real display, and those forced timing work better than whatever macOS and the real display were able to negotiate by themselves.
You can also use Better Display to control various twiddly features (like HiDPI and HDR) that may be why the real display is getting confused. The way this seems to work is that Better Display correctly advertises whatever HiDPI wants, then just copies the image that is drawn to the real display, whereas negotiating with the real display for HiDPI (or HDR) seems to be another area where either Apple makes mistakes or the real display hardware makes mistakes.
So give it a try. As I say, it worked for me.
I only seem to get flickering (rapid pulsing) of the display in HDR mode, no matter what setting the Dell U3223qe is set to, I have tried combinations of them all.
Including change the cables and running into that weird none RGB mode in HDMI.
The second I turn off HDR the flickering goes away. Bear in mind this monitor is 3 days old direct from Dell. I have already sent them a ticket for an answer, though from the amount of people complaining about flickering with third party displays, mostly Benq, LG and Dell, it appears this is a Mac thing which is a typical to the silicone macs.
Maybe Apple did not put HDR on their own macs as they knew there was this hardware/software issue they could not resolve. A sort of limitation elimination type of deal.
Also noticed my Dell and Mac do not play well if I turn off the screens power and close the macs lid but leave the USB C cable and upstream cable plugged in before I go to bed.
Each morning I wake up and find the Mac is black screen and have to force restart.
Apple - buy our expensive products we have limited because these are the only bits we can reliably make work with our own stuff. You’ll love it.
Including change the cables and running into that weird none RGB mode in HDMI.
The second I turn off HDR the flickering goes away. Bear in mind this monitor is 3 days old direct from Dell. I have already sent them a ticket for an answer, though from the amount of people complaining about flickering with third party displays, mostly Benq, LG and Dell, it appears this is a Mac thing which is a typical to the silicone macs.
Maybe Apple did not put HDR on their own macs as they knew there was this hardware/software issue they could not resolve. A sort of limitation elimination type of deal.
Also noticed my Dell and Mac do not play well if I turn off the screens power and close the macs lid but leave the USB C cable and upstream cable plugged in before I go to bed.
Each morning I wake up and find the Mac is black screen and have to force restart.
Apple - buy our expensive products we have limited because these are the only bits we can reliably make work with our own stuff. You’ll love it.
Mentioned this on Apple Discussions, but dropping a short version here since we're all trying to figure this out.
Just purchased an M2 Mac Mini Pro. As soon as I booted the computer - going through initial setup, I had intermittent flickering and vertical line issues. I used the same exact AOC U2879VF 4K/60Hz monitor I've been using with my Mid-2014 MBP. It comes and goes. I haven't seen the vertical lines in 2 days since trying a different cable, but still get flickering.
Apple support escalated me on the phone to whatever the 2nd tier is (senior?) & said it's a faulty port. I *think* this faulty-port issue could be a red herring based on my experience and what I'm reading from many others.
I've tested this out more. I'm pretty convinced it's a syncing issue of some kind. at 60hz, I see flickering every so often. At 50hz, sometimes there's a second of a black screen. At 30hz, no flickering. I had the vertical lines, but haven't seen that in a bit. I also noted that certain website pages (like with dense text and color shades) caused the issue to trigger. Flickering happens across the whole screen. I've seen some suggest getting a USB C to HDMI, but WHY should I have to tie up a USB C port when I paid to have an HDMI?
Incidentally, my first call on this machine was the ridiculous smooth plastic bottom. Less than 5 lb computer...wires hanging off....smooth bottom on smooth desk....as Apple likes to say, HELLO!?????
Just purchased an M2 Mac Mini Pro. As soon as I booted the computer - going through initial setup, I had intermittent flickering and vertical line issues. I used the same exact AOC U2879VF 4K/60Hz monitor I've been using with my Mid-2014 MBP. It comes and goes. I haven't seen the vertical lines in 2 days since trying a different cable, but still get flickering.
Apple support escalated me on the phone to whatever the 2nd tier is (senior?) & said it's a faulty port. I *think* this faulty-port issue could be a red herring based on my experience and what I'm reading from many others.
I've tested this out more. I'm pretty convinced it's a syncing issue of some kind. at 60hz, I see flickering every so often. At 50hz, sometimes there's a second of a black screen. At 30hz, no flickering. I had the vertical lines, but haven't seen that in a bit. I also noted that certain website pages (like with dense text and color shades) caused the issue to trigger. Flickering happens across the whole screen. I've seen some suggest getting a USB C to HDMI, but WHY should I have to tie up a USB C port when I paid to have an HDMI?
Incidentally, my first call on this machine was the ridiculous smooth plastic bottom. Less than 5 lb computer...wires hanging off....smooth bottom on smooth desk....as Apple likes to say, HELLO!?????
I fired up my old Mac Pro 5,1 with its 7950 Mac edition GPU. Via display port cable, I tried Mojave, Monterey, Ventura and windows 10 and 11. No flickering with the U3223qe in HDR mode if anything the display text looked sharper. I then used the same cable with the M2, flickering in Ventura in HDR but only with a grey background. Weird.
Then got a shorter Type C cable and there was less flickering (almost none) in HDR mode on the M2 with a grey background.
Absolutely no flickering in non HDR mode with any cable with the M2.
Then got a shorter Type C cable and there was less flickering (almost none) in HDR mode on the M2 with a grey background.
Absolutely no flickering in non HDR mode with any cable with the M2.
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hardwickj
macrumors 6502
First, many of the posts (or fix suggestions) in this thread are referring to completely different issues, with many essentially amounting to a poor quality cable/connection. THAT IS NOT THE ORIGINAL ISSUE POSTED BY THE OP. I've been dealing with this issue off & on for 1.5 years, as soon as I read their description I recognized it.
I have 3x Dell U2720Q 27" 4k monitors, two of which are connected w/ Anker TB4 cables and one w/ an Anker USB-C cable and I've had this happen on every one of them at one time or another. A few important details for when it happens:
I have 3x Dell U2720Q 27" 4k monitors, two of which are connected w/ Anker TB4 cables and one w/ an Anker USB-C cable and I've had this happen on every one of them at one time or another. A few important details for when it happens:
- This is not a flickering in the sense that the monitor turns off/on (e.g. losing signal), etc. It's more like the monitor is suddenly operating at 15hz instead of 60, but with some weird scanning issue that causes the appearance of vertical lines. Again, it's literally a 10-15hz flicker, not an on, then off for a few seconds, then on again (which is typical of a poor cable/connection)
- It disproportionately affects darker colors. Pure white backgrounds do not seem to show the flicker at all. Dark grey backgrounds feel like a sledgehammer coming out of the screen to pummel your brain.
- Again, IT IS NOT A CABLE ISSUE. When it happens, I can unplug my laptop from the monitor completely, and it continues to flicker until the monitor goes into power save mode or you turn the monitor off.
- Power cycling, unplugging and waiting for X seconds before reconnecting power, going into settings and performing a factory reset, etc, do nothing to fix it. The only thing I've found to fix it is to literally just wait. In the case of my U2720Q's, it takes about an hour, but it does gradually go away.
- In the case of my U2720Q's, I actually get some ghosting of the applications I was using when the flickering first happens. Even when I unplug my MacBook Pro M1 Max, the ghosted applications still appear until the monitor goes to sleep. However, that ghosting seems to fade away within ~10 minutes, much quicker than the flickering overall.
hardwickj
macrumors 6502
My best guess is that there is a panel controller(s) used by many of the monitor manufacturers which experiences some kind of communication mishap w/ Apple Silicon Mac's, since they use a different display subsystem from Intel Apple Macs (presumably based on the same subsystem used by iOS). I don't know enough about LCD controllers to understand how or even if that's possible, but given that once the flickering is triggered it tends to stay around for a bit even when the computer has been disconnected, that's the only logical explanation that I can come up with.
hardwickj
macrumors 6502
That's a great question but given how infrequently it happens (once every couple months for me), and how little most users use an iPad w/ an external display, that would be very difficult to reproduce.
i'd filed a bug report about it a year ago. i recently got a response from apple saying to let them know if it was any better as there had been changes in 13.3.1 that "may have resolved the issue".
i'm pretty sure i've still experienced it fairly recently - but it is a weirdly intermittent problem, where it can sometimes happen daily, or sometimes go weeks between episodes - so i can't confirm which version i was running when it last occurred.
i'm glad i've at least got some evidence that they're looking into the issue. we'll see what happens.
edit: almost immediately the issue started up for me again. 🙁
i'm pretty sure i've still experienced it fairly recently - but it is a weirdly intermittent problem, where it can sometimes happen daily, or sometimes go weeks between episodes - so i can't confirm which version i was running when it last occurred.
i'm glad i've at least got some evidence that they're looking into the issue. we'll see what happens.
edit: almost immediately the issue started up for me again. 🙁
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This is truly one of the strangest computer problems I have encountered in decades. I've had to take a video of it and also check with my friends to see if the problem wasn't just in my head 😉 It seemed impossible to me that it wasn't the display's fault and I even managed to reclaim one display at the manufacturer, based on the video footage 😉 Unfortunately, the new display started suffering from this problem within a few days.
I have an MBP M1 14", and two ViewSonic VP2785-4K, connected via CalDigit TS3+ (USB-C and DP). The first time this happened to me was about 2 years ago, not long after I got the 2nd display. I never use the build-in display, my MBP is always closed.
My observations:
1) The error also occurred with another MBP M1 borrowed from the work, with completely different software.
2) The problem never occurs when only 1 (external) display is connected.
3) It doesn't matter how the displays are connected. The error can happen when connected via dock (USB-C or DP) or directly (HDMI or USB-C). Connecting to a different port or restarting the display doesn't help at all.
4) The error manifests itself very irregularly. Sometimes every few hours, sometimes after a few weeks.
5) The only solution is to completely reboot the computer or wait a few hours.
6) The error always starts only on one of the displays, but when it occurs, there is a good chance that after some time (minutes or tens of minutes) the other display will also start flickering.
7) The intensity of the flickering can be influenced by the displayed content. Bright areas and alternating contrasts areas seem to be the most problematic.
8) Strangest issue is the ghosting effect. I absolutely don't understand how this can be possible. It looks like burnout pixels with some sort of transparency, like if your display has been showing the same image for many months or years and then you changed it. It can't be removed by, say, scrolling the window or displaying a different content, it is there until you reboot. But strangely enough, it is not present on screenshots or via screen sharing.
I have an MBP M1 14", and two ViewSonic VP2785-4K, connected via CalDigit TS3+ (USB-C and DP). The first time this happened to me was about 2 years ago, not long after I got the 2nd display. I never use the build-in display, my MBP is always closed.
My observations:
1) The error also occurred with another MBP M1 borrowed from the work, with completely different software.
2) The problem never occurs when only 1 (external) display is connected.
3) It doesn't matter how the displays are connected. The error can happen when connected via dock (USB-C or DP) or directly (HDMI or USB-C). Connecting to a different port or restarting the display doesn't help at all.
4) The error manifests itself very irregularly. Sometimes every few hours, sometimes after a few weeks.
5) The only solution is to completely reboot the computer or wait a few hours.
6) The error always starts only on one of the displays, but when it occurs, there is a good chance that after some time (minutes or tens of minutes) the other display will also start flickering.
7) The intensity of the flickering can be influenced by the displayed content. Bright areas and alternating contrasts areas seem to be the most problematic.
8) Strangest issue is the ghosting effect. I absolutely don't understand how this can be possible. It looks like burnout pixels with some sort of transparency, like if your display has been showing the same image for many months or years and then you changed it. It can't be removed by, say, scrolling the window or displaying a different content, it is there until you reboot. But strangely enough, it is not present on screenshots or via screen sharing.
rushmere
macrumors 6502
I have a M1 Mac Mini. My main display is a BenQ PD2705U, and my second monitor is an old LG 27UD69.
The LG monitor is getting ready for replacement (it has discolouration issues around the edges), but it's never flickered.
I used to get flicker on my BenQ monitor on average about once every month or two. Since updating to Ventura a few weeks ago, it's now regularly happening 2-3 times per week. I've tried every potential solution I can find, but nothing has worked for me. I just have to stop working for 20-30 minute, and it eventually stops flickering.
It's now reached the point where it's seriously disrupting my work, so despite the very high price, I'm thinking about getting an Apple Studio Display. While some people don't get the issue at all, it seems to be a bit of a lottery. It seems that the Studio Display is the only way to absolutely guarantee that it will always work without flickering? Is that a correct assumption?
The LG monitor is getting ready for replacement (it has discolouration issues around the edges), but it's never flickered.
I used to get flicker on my BenQ monitor on average about once every month or two. Since updating to Ventura a few weeks ago, it's now regularly happening 2-3 times per week. I've tried every potential solution I can find, but nothing has worked for me. I just have to stop working for 20-30 minute, and it eventually stops flickering.
It's now reached the point where it's seriously disrupting my work, so despite the very high price, I'm thinking about getting an Apple Studio Display. While some people don't get the issue at all, it seems to be a bit of a lottery. It seems that the Studio Display is the only way to absolutely guarantee that it will always work without flickering? Is that a correct assumption?
i've actually gotten what seems to be a somewhat engaged response through apple feedback. although their next request was for me to capture a sysdiagnose the next time it happens, and of course... it hasn't happened for a couple weeks now 🙄
but for anyone else going through apple feedback for it, try to include that data, as perhaps it'll help in pinpointing whats causing this cursed issue.
the steps they gave:
1. Reproduce the problem or wait for the problem to happen again. If an error message appears, leave the error dialog on screen.
2. Capture a screenshot. (The timestamp will show us where in the logs in to look.)
3. As soon as you see the problem happening, hit Shift-Cmd-Ctrl-Opt-period to trigger the sysdiagnose. The screen should flash to indicate it has started.
4. When it is done, Finder will open a window to the location of the log file in /var/tmp/. Attach that file back to us, as well as the screenshot that you took.
but for anyone else going through apple feedback for it, try to include that data, as perhaps it'll help in pinpointing whats causing this cursed issue.
the steps they gave:
1. Reproduce the problem or wait for the problem to happen again. If an error message appears, leave the error dialog on screen.
2. Capture a screenshot. (The timestamp will show us where in the logs in to look.)
3. As soon as you see the problem happening, hit Shift-Cmd-Ctrl-Opt-period to trigger the sysdiagnose. The screen should flash to indicate it has started.
4. When it is done, Finder will open a window to the location of the log file in /var/tmp/. Attach that file back to us, as well as the screenshot that you took.
i haven't but i wouldn't be surprised if anyone actually investigating the problem hasn't come across it in a cursory search. i'll mention it whenever i'm able to capture the issue and send a follow up message though 🙂
Cheers, if you have an open ticket with them, there are some very helpful posts in this thread with good video and screenshot evidence of the issue.
ex.
crackout666
macrumors newbie
I have the exact same problem with my MBP M2 Max and a HP27f 4k screen.
"Luckily" this behaviour is only triggered when macOS is in NightShift and the screen is connected through my Thunderbolt-Hub (Anker PowerExpand+ 11-in-1). During "daylight" operation the problem does not occur.
"Luckily" this behaviour is only triggered when macOS is in NightShift and the screen is connected through my Thunderbolt-Hub (Anker PowerExpand+ 11-in-1). During "daylight" operation the problem does not occur.
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I have a BenQ 4k external monitor connected via HDMI directly to my M1 Pro 16". It flickers sometimes. I need to open up the display settings below and toggle "High Dynamic range" to on. The flicker goes away immediately.
It seems like macOS forgets the HDR setting sometimes, which causes it to flicker.
It seems like macOS forgets the HDR setting sometimes, which causes it to flicker.
So another user here using an M1 Mac book Air. This issue has existed for me since day dot with this machine. I own an MSI 1440p monitor. I run this monitor in 1440p on a DP connection at 165 hrz. Obviously as we all know its the classic situation of every now and then horrific ghosting, with verticle lines all over the screen.. happens randomly but I do think I have a couple of instances where I see the trigger and its generally when windows are open over apps. Like in Slack, using workflows window in the application. If I have a lot of apps open this can trigger the state. I have a feeling that the more icons I have on my desktop, this can make the issue worse. However one way I can almost always trigger it manually outside of the above, is to open the Guardian news Website, and open the live news feed (ukraine is a good option). I keep feed at the start of the page, do not scroll down and immediately I see the lines, which then progresses to ghosting over the minutes. If anyone who is engaging with Apple wants a way to trigger it every time this works for me, and it may work for you.
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rushmere
macrumors 6502
This is such a weird problem, as although many of us are seeing exactly the same symptoms, the triggers and solutions seem to be quite random.
I'm getting regular flickering now with my BenQ monitor to such an extent that it's seriously disrupting my work, but I haven't found anything that stops it. Toggling "High Dynamic Range" makes no difference for me.
I'm just about ready to open my wallet and buy an Apple Studio Display, as I can't keep stopping work multiple times every week to wait for the problem to go away.
rushmere
macrumors 6502
I don't get the ghosting, but I do get the rapid flickering, which makes my Mac unusable for up to 30 minutes each time it happens.
Oddly, it started just now immediately on viewing The Guardian website! This is such a weird (and extremely annoying) problem!
UPDATE: After the flickering died down, I opened the Guardian website again, and the flickering immediately came back. How odd! So far, it's only happening with Safari; if I open the website in Firefox, I don't get any flickering.
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rushmere
macrumors 6502
So I've tried this multiple times today, and visiting www.guardian.com in Safari consistently triggers the screen flickering for me.
It thens takes around 10-15 minutes for the flickering to stop. I can't find anything to stop it - closing Safari makes no difference, I just have to wait.
I also use Mission Control and multiple desktops (i.e. spaces) on my Mac. I've changed the background on my first desktop to a simple mid-grey colour, and that shows the flickering more clearly. I can see a ghost image of the Guardian website on that space for about 30 seconds (Safari is running on a different desktop), even after completely closing Safari, and the ghost image slowly fades away, although the flickering continues for some time after.
Why would visiting a specific website cause the screen to flicker? This is just bizarre.
It thens takes around 10-15 minutes for the flickering to stop. I can't find anything to stop it - closing Safari makes no difference, I just have to wait.
I also use Mission Control and multiple desktops (i.e. spaces) on my Mac. I've changed the background on my first desktop to a simple mid-grey colour, and that shows the flickering more clearly. I can see a ghost image of the Guardian website on that space for about 30 seconds (Safari is running on a different desktop), even after completely closing Safari, and the ghost image slowly fades away, although the flickering continues for some time after.
Why would visiting a specific website cause the screen to flicker? This is just bizarre.