Not sure if it makes a difference but I also enabled flexible scaling using betterdisplay.
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5K2K at 120Hz with Mac Mini M4
- Thread starter Newgoblin49
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Any M5 user to test? The one I got could not even drive a 4K portable monitor.
So, I believe I managed to make my Macbook Pro M4 Pro (12/16) run my external 32:9 monitor at HiDPI 3840x1080@ 144 Hz with Better Display.
OOTB, previously, I could only run HiDPI 3328x936@144Hz, which made GUI scaling too large, and basically defeated the purpose of having a 32:9 screen, as so much screen real estate was lost.
- Monitor is Philips Evnia 49" 49M2C8900L
- Cable used is DP to DP 1.4, the one that came with the monitor
- Dock used is a Dell WD19TB
I followed this Reddit article:
It's the usual Virtual Display setup, but I fully expected the virtual screen to work at 60Hz, as that's what I read all over the internet.
After creating the virtual screen, it defaulted to 75Hz as the only dropdown option, and I immediately noticed the difference and scrolling being sluggish.
Well, I went ahead and added a custom refresh rate of 144Hz to the Source Display, disconnected it, connected it, and 144Hz appeared in the MacOS display drop-down.
It was smooth, but I still suspected it was running at 75Hz, as it could very well be a placebo. Time for some testing, then.
I nuked the virtual display setup and set the Philips screen to 60, 75Hz, 120Hz, 144Hz.
I would then test ufotest, check the OSD output to check the Hz monitor is displaying, a couple of other Hz test websites, and, of course, scrolling in a couple of MacOS UI system areas.
For each test, I would do side to side against the MacBook screen set to ProMotion and High Power mode.
Well, the 60 and 75Hz difference was apparent between Macbook screen and the Philips Ultrawide.
120 and 144Hz, observed that Philips' screen behaviour matched that of the MacBook screen.
I then fired up the Virtual Screen, set the resolution to 3840x1080@144Hz, and I could tell it's definitely not running at 75Hz as its scrolling smoothness, cursor movement matched that of the MacBook screen.
This is my first MacOS experience, so I'm not aware at what Hz specific system/app areas are rendered, so I'll give it another go and maybe do some slow-mo 120fps video recordings w/ S23 Ultra and iPhone 17 Pro and analyze if the difference between noVirtual/Virtual screen setups is apparent.
Just my two cents on this very helpful thread.
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I must say, Windows is a walk in the park compared to MacOS when it comes to multiple display management and scaling, and I am actually shocked there has been no response from Apple to this major bug/gap/limitation for over a year. Especially since this worked on previous M1/M2/M3 silicon lines. They're lucky Windows became an ad-filled, bloatware, sluggish system with 11.
For a company that boasts its products as productivity/creator-oriented, to me, it feels like Displays was developed with only one screen in mind.
OOTB, previously, I could only run HiDPI 3328x936@144Hz, which made GUI scaling too large, and basically defeated the purpose of having a 32:9 screen, as so much screen real estate was lost.
- Monitor is Philips Evnia 49" 49M2C8900L
- Cable used is DP to DP 1.4, the one that came with the monitor
- Dock used is a Dell WD19TB
I followed this Reddit article:
It's the usual Virtual Display setup, but I fully expected the virtual screen to work at 60Hz, as that's what I read all over the internet.
After creating the virtual screen, it defaulted to 75Hz as the only dropdown option, and I immediately noticed the difference and scrolling being sluggish.
Well, I went ahead and added a custom refresh rate of 144Hz to the Source Display, disconnected it, connected it, and 144Hz appeared in the MacOS display drop-down.
It was smooth, but I still suspected it was running at 75Hz, as it could very well be a placebo. Time for some testing, then.
I nuked the virtual display setup and set the Philips screen to 60, 75Hz, 120Hz, 144Hz.
I would then test ufotest, check the OSD output to check the Hz monitor is displaying, a couple of other Hz test websites, and, of course, scrolling in a couple of MacOS UI system areas.
For each test, I would do side to side against the MacBook screen set to ProMotion and High Power mode.
Well, the 60 and 75Hz difference was apparent between Macbook screen and the Philips Ultrawide.
120 and 144Hz, observed that Philips' screen behaviour matched that of the MacBook screen.
I then fired up the Virtual Screen, set the resolution to 3840x1080@144Hz, and I could tell it's definitely not running at 75Hz as its scrolling smoothness, cursor movement matched that of the MacBook screen.
This is my first MacOS experience, so I'm not aware at what Hz specific system/app areas are rendered, so I'll give it another go and maybe do some slow-mo 120fps video recordings w/ S23 Ultra and iPhone 17 Pro and analyze if the difference between noVirtual/Virtual screen setups is apparent.
Just my two cents on this very helpful thread.
--------------
I must say, Windows is a walk in the park compared to MacOS when it comes to multiple display management and scaling, and I am actually shocked there has been no response from Apple to this major bug/gap/limitation for over a year. Especially since this worked on previous M1/M2/M3 silicon lines. They're lucky Windows became an ad-filled, bloatware, sluggish system with 11.
For a company that boasts its products as productivity/creator-oriented, to me, it feels like Displays was developed with only one screen in mind.
@ClassicMartini can you share any details as to how you managed to get this to work? I have a Mac Mini M4 Pro, connected to the LG 5k2k OLED via Thunderbolt (DP over TB), and no matter what I try, I cannot get Better Display to offer the option to use a 10k4k virtual screen. I can set up plenty of other resolution virtual screens; they work fine, and I can create the 10,240 x 4320 virtual screen setting in Better Display, but when I'm actually streaming the virtual screen to the LG, it only shows lower-resolution virtual screens to select from.
ClassicMartini
macrumors member
Sorry, no. Maybe ask the guy who invented Better Display (have you purchased it? he's really helpful).
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Not that I don't want to (help you), just can't recall the fiddly-diddly procedure. Do recall it being very frustrating.
Warning, 'rant' incoming:
After several weeks of playing with ways to achieve The One True Resolution From The Bible of Jobs (mostly according to other people) realised I wasn't actually doing any WORK. Threw better display away a few months after purchase. Not that its bad software. In fact its one of the more polished things I've ever used.
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Since then I've embraced a more er, 'dynamic' idea that orbits around Field of View in relation to best resolution with what you've got. How far away you are from monitor, some OS settings, bunch of little things. Stuff that Gets Work Done.
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I also got my dream monitor since that post, and you might be shocked at the resolution(s) I settled at...
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Quick update on this one. Dell WD19TB turned out inadequate as it's only TB3, so bandwidth was near max just by running the screen.
As soon as I would play lossless music, or initiate a file transfer from an external SSD, bandwidth would max out and screen flicker would happen with color artifacts all over the screen.
I connected the monitor and MacBook with a C-to-C TB4 cable directly, and it's been working flawlessly ever since.
Slightly off topic, but my parents are considering switching their PC to a mac m4 (or m5) mini.
They currently have their PC desktop displays (2x 24" 1200p dell 60hz ultrasharps, soon to be 2x 27" 1440p 120hz dell ultrasharps) "scaled/zoomed in" to 125%. However I have read with mac mini's, scaling/zooming the desktop can appear blurry on a 27" 1440p 120hz display. I also read this issue is resolved if you use a 4K display.
Is any of this correct?
Thanks!
They currently have their PC desktop displays (2x 24" 1200p dell 60hz ultrasharps, soon to be 2x 27" 1440p 120hz dell ultrasharps) "scaled/zoomed in" to 125%. However I have read with mac mini's, scaling/zooming the desktop can appear blurry on a 27" 1440p 120hz display. I also read this issue is resolved if you use a 4K display.
Is any of this correct?
Thanks!
Not sure if I remembered to answer you about this. With my M2 Max MBP 16":
- HDMI 3 works just fine for the 21:9 side. 5120x2160 @ 120 Hz w/ 3840x1620 HiDPI.
- HDMI 2 seems to be exactly the same.
I tested with both HDMI 2 and 3 and that side only offers 60 Hz no matter what. It also seems to get detected as 3840x2160 for some reason and even adjusting BetterDisplay settings I could not get it faked to a 2560x2160 @ 120 Hz.
I had the same lack of HiDPI issue with the 11:9 side and BetterDisplay fixed that. Just very weird behavior, like MacOS just doesn't understand what 2560x2160 is!
I'm getting a new machine for work and I'm hoping the M5 Pro/Max would be out soon so I can get that. Otherwise I likely have to go M4 and I dread running into that "lack of 3840x1620" issue on the Samsung G95NC.
Did you ever manage to fix this on your M4?
Looks like this is not fixed in the M5 MBP either (link)
So it looks like the last chip that it worked on was the M3 Pro? (Doesn't work on M4, M4 Pro, and now M5)
So it looks like the last chip that it worked on was the M3 Pro? (Doesn't work on M4, M4 Pro, and now M5)
Your link is the base M5 MBP, not M5 Pro MBP. For M5 it makes sense that it doesn't work since it only supports up to 6k without DSC and up to 8k with DSC, so it's limited to 3008x1269 HiDPI for displays without DSC.
That’s right. That post was to say M5 doesn’t work.
Now newer Reddit posts say m5 max doesn’t work either. We are out of luck. Wait for m6 I guess.
Hello, I opened a thread on Apple forum with what seems to be a very related issue:
I am currently in contact with Apple support, I demoed the issue with them and we went through collecting diagnostics etc. I guess others reporting those issues can only increase the chance of it being recognized.
I am currently in contact with Apple support, I demoed the issue with them and we went through collecting diagnostics etc. I guess others reporting those issues can only increase the chance of it being recognized.
I can confirm we have the same issue on M5 Pro chip, on a Macbook Pro 16 inch.
Can use 3360x1418 or 5120x2160.
BetterDisplay adding 3840x1620 is not working. Using a LG 40WP95C for reference.
Can use 3360x1418 or 5120x2160.
BetterDisplay adding 3840x1620 is not working. Using a LG 40WP95C for reference.
anthonymoody
macrumors 68040
This is absolutely insane. Am I never going to trade up from my M1 Max because it's the only way to keep using my 5k2k LG at 3840 x 1620???
Author of this thread said Apple are aware of it! So let's hope it a software-thing, not hardware..
More: https://discussions.apple.com/thread/256265624?sortBy=oldest_first&page=1
T'hain Esh Kelch
macrumors 604
Very happy with mine. Getting 3840x1620@120hz out of the box on my M4 Pro mini using TB4. It had some issues with connected drives when going to sleep, but a firmware update fixed that. No other issues. Well, the only issue I have is that my Mini boots faster than the display gets ready after being turned on, and in the old days it was the other way around.. lol
Riot Nrrrd
macrumors 6502a
Using a high speed HDMI gives me 3840x2160 @60Hz.
Going back to the original thunderbolt-cable from LG: back to 3360x1418 @72Hz..
anthonymoody
macrumors 68040
I'm glad to see that, though the user in that thread trying to help is frankly infuriating.
sammcj
macrumors member
I upgraded from a M2 Max to a M5 Max and have spent the last few days trying to figure out why the M5 fails to provide the same clean 4k output as the M2 did. I've done a bit of a long form write up of my notes and findings in this post: https://smcleod.net/2026/03/new-apple-silicon-m4-m5-hidpi-limitation-on-4k-external-displays/ (was discussed on HN today as well)
this is a great article, thank you! But I think the display example (4K 32") that you included there might be a bit misleading.
LowDPI for a resolution on the screen that has the same resolution means the image is rendering in native pixel-to-pixel form. Does this make text more blurry than when an additional 8K->4K transformation (which we have in case of HiDPI 4K) is applied? I'm not sure.
That argument is somewhat exaggerated. Because macOS’s UI is not oversized in this case. Basically, 3360x1890 on 31.5" equals 122 DPI which is much higher than recommended DPI for Apple's external displays (110 DPI). Apple laptops' recommended DPI value is 127 which is higher than 122 but still nowhere near 140 (like 4K on 31.5").
I would say DPI of 140 means very small UI.
This issue is particularly relevant for owners of 5K2K 40" monitors. They really need 3840x1620 HiDPI resolution. Because native 5120x2160 is 140 DPI which means too small UI. But 3360x1418 is 91 DPI which gives too large UI. And there is no intermediate resolution.
I guess, such a monitor would be a great example for your article.
Forcing 2x scaling has been known to improve text clarity vs native 1:1, on otherwise lower PPI screens. The 1440 27" and 34" ultrawides, and then larger than 48" 4k TVs etc, these are known to be improved by forcing 2880p and 8k HiDPI mode (often needs apps like BetterDisplay Pro). To my understanding, this gives more breathing room for text fringing to not occur as much since the sub-pixel rendering of fonts happen on 2x dimension, then the downscaling to the display is like an extra step of anti-aliasing that wouldn't have happened when just 1:1.
Absolutely brilliant article! Way more in-depth than what I know about the external display bag of nightmares that MacOS has.
I'm going to receive a M5 Pro MBP 16" in a month or so, and I'm dreading how it will behave with my Samsung G95NC 7680x2160. I've been running it fine as two monitors on my M2 Max MBP at 5120x2160 + 2560x2160 (3840x1620 + 1920x1620 HiDPI aka 7680x3240 + 3840x3240 render res) because that's the only way to get adequate scaling.
It's just ridiculous that Apple's scaling system is such a turd with all these limitations, and they seem to adamantly refuse to change it.
PS. Do you think it would be possible to swap the DCP firmware from M5 Max -> M5 Pro? I'm curious if the additional display capabilities of the M5 Max (can run an extra display etc) are just cut out of the M5 Pro on firmware level rather than being an actual hardware limitation.