Why is my Mac mini M4 Pro display resolution low and how can I adjust it?

Full 5K is 5120x2880 pixels. Your monitor has 5120x2160 pixels – in other words, ultra-wide aspect ratio obtained by "adding stuff to the sides of a 4K monitor" or "chopping off part of the top and bottom of a 5K monitor."

So I'm guessing it is a LG 40" UltraWide (40WP95C) WUHD 5K2K Nano IPS Curved Monitor .

If so, it has a pixel density of roughly 139 PPI. Text in non-Retina, native mode, would be uncomfortably small.

• At your preferred setting, text would be almost exactly the same size as on a 27" 2560x1440 monitor.
• At the "like 3360x1418" setting, text would be almost exactly the same size as on a 24" 1920x1080 monitor.

I'm not sure why your preferred setting went away – whether this is just a software issue (one that a future macOS update might remedy, or that you might be able to overcome with third-party resolution switching software) - or a change in the video support of M4-family processors (relative to M1/M2/M3-family chips).

For what it's worth, "like 3840x1620" would imply the use of an internal canvas that had 7680x3240 pixels. A 32" Apple 6K Pro Display XDR has a native resolution of 6016x3384 pixels. So the mode which you want to use would require a canvas with about 22% more pixels than the total number of pixels on a 32" 6K display.

MatNeh wrote:

Good point, we aren’t being totally accurate when we say that we want “3840 x 1620.” What we’re asking for is to use the “looks like” 3840x1620, but MacOS actually uses the full 5120 x 2160 res and smooths the fonts really cleanly with all those extra pixels.

In Retina "looks like 3840x1620" mode,

• The Displays Settings, or "UI looks like" resolution of 3840x1620 would be what applications use when sizing text and objects.
• The internal drawing canvas would have 7680x3240 pixels. As wide, though not as tall, as native resolution of the panel on an 8K (7680x4320) display.
• The Mac would downscale the 7680x3240 pixel canvas to get 5120x2160 pixels worth of data for the display.

In "3840x1620 (low resolution)" mode

• The internal drawing canvas would have 3840x1620 pixels.
• The Mac would upscale the 3840x1620 pixel canvas to get 5120x2160 pixels worth of data for the display. Like with expanding a MP3 file to a full-size uncompressed CD-Audio-quality file, this would increase the total volume of data, but would not add any information to the signal beyond the 3840x1620 pixels' worth present in the canvas.

If your Mac supported both modes, and you switched back and forth between them quickly, you'd see the text becoming cleaner when you switched to the Retina mode, and less-well-defined when you switched to the "low resolution" one.

Hopefully now someone at Apple will do something about it. Gotta thank Filipe at 9to5 that agreed to write about this.

Thank you for your reply ☺️

Are there any newer experiences meanwhile? I'm about to buy a Mac Mini m4 Pro, as soon as an OS Update has implemented HiDPI support for 5k2k. I've got 2 LG 5K Ultrawide I want to use with it. Thanks

Hello,

I have the same problem with my MacBook Pro M4 Max connected to an LG 34WK95UP-W.

The resolution of 3840 x 1620 is missing.

Any updates here yet?

I have the latest macOS 15.4.1 installed.

Hello,

Any news from any of you?

I've just installed MacOS 15.5 and I'm still missing the 3840 x 1620 resolution setting.

M4 Mac Mini + Studio Display

Display 5120 * 2880

Default 2560 * 1440

You have a native 5120 * 2160 so a different aspect ratio. Try Show all resolutions on the Display prefs and see what is available? Failing that take a look at SwitchResX or EasyRes or etc.

Servant of Cats wrote:

So I'm guessing it is a LG 40" UltraWide (40WP95C) WUHD 5K2K Nano IPS Curved Monitor

In my case, it's an LG 34" 34BK95U-W UltraFine (flat panel), but I see the same issue. As one who used the 3840x1620 setting routinely and now finds it unavailable on my new 16" M4 Pro MBP, it's annoying. It's even more annoying because I frequently switch back and forth between that Mac (my personal one) and my work Mac, a 16" M1 Pro MBP, that does support 3840x1620. So now, the text sizes are different between the two every time I switch. Major PITA.

FWIW, my LG display is Thunderbolt 3 and connected as such, so it seems unlikely this is a cabling/bandwidth issue. Especially since older Macs had no problem in the same setup, obviously.

For what it's worth, "like 3840x1620" would imply the use of an internal canvas that had 7680x3240 pixels. A 32" Apple 6K Pro Display XDR has a native resolution of 6016x3384 pixels. So the mode which you want to use would require a canvas with about 22% more pixels than the total number of pixels on a 32" 6K display.

As you said in your other reply, the M4 Pro should have no problem with that...the M1 Pro doesn't, nor does the 2019 16" Intel Core i9 MBP that is my prior personal Mac.

Your supposition about the internal canvas is correct. When taking a full-screen screenshot with either of those other Macs connected to the display, the output is a 7680x3240 image.

I've submitted feedback to Apple on this, and suggest anyone else with this issue does the same:

Feedback - MacBook Pro - Apple

same issue here with a Lenovo P40w-20 (LG panel) - works fine on a MBP 16" M1 pro with 3840x1620 - on the new Mac mini M4 Pro this resolution is missing (using BetterDisplay but with 60 Hz refreshrate as workaround) - VERY annoying

I was eventually able to get BetterDisplay to work if I created a Virtual screen with 3840x1620 resolution and then mirror it to my actual display. However, my mouse keeps getting stuck and using a corner of the screen to enter sleep mode doesn't work so it's not a good solution.

As someone who also has the LG 34" 34BK95U-W UltraFine display (but no M4 Mac), I have to ask - if you think 5120x2160 is "too small", then why did you buy a 5K2K display? You could've just bought a smaller 30" WQXGA 2560x1600 display or something and use the full resolution rather than upscaling.

Not saying that Apple shouldn't fix this of course, but I'm curious. 🤷🏼

Also, everyone has said the M1-based Macs are fine - what about M2 or M3? No one out there in thread-land with any of those who can chime in?

Good point, we aren’t being totally accurate when we say that we want “3840 x 1620.” What we’re asking for is to use the “looks like” 3840x1620, but MacOS actually uses the full 5120 x 2160 res and smooths the fonts really cleanly with all those extra pixels.

Another way to state this:

5120x2160 on 40” 21:9 display is 139 dpi

3840x1620 on 40” 21:9 display is 104 dpi

3360x1418 on 40” 21:9 is 91 dpi

what we want is to use 139 pixels to represent a 104 pixel inch-sized object, which means it can have smooth edges.

The alternative currently being offered is 3360x1418 (91 dpi) which is clean but too big (most lower res monitors are scaled for 96 dpi)

Also if I have a second monitor at 96-100 dpi, fonts will look similar on both if we can use this setting

So I am planning to get a new Macbook Pro M4, connecting it to my Dell U4021QW over thunderbolt - with my Macbook Pro M1 I used a resolution of 3840 x 1620 - so that's for now not possible anymore. Is that right?