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I have an Ultra 3 MacStudio and the LG4025QW. I can run the display with a 3840x1620 HiDpi resolution with 120Hz without any problems. MY notebook - a MacBookPro M3Max can do it as well.

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You are literally sharing the monitor that doesn’t have an issue. Any machine including the Mac Mini base can run that monitor without any sort of issue.
 
I have an M3 Ultra Mac Studio and the Dell U4025QW. I can run the display with a 3840x1620 HiDPI resolution at 120Hz without any problems. My notebook - a MacBook Pro M3 Max - can do it as well.
Good to know, but we already knew that the Dell U4025QW works - even with M4-based Macs :)

We need someone with an M3 Ultra Mac Studio and a 5K2K monitor that is NOT the Dell U4025QW to chime in, in other words …

(I’m sure it probably works since it’s an M3, but it would be nice to verify it.)
 
Good to know, but we already knew that the Dell U4025QW works - even with M4-based Macs :)

We need someone with an M3 Ultra Mac Studio and a 5K2K monitor that is NOT the Dell U4025QW to chime in, in other words …

(I’m sure it probably works since it’s an M3, but it would be nice to verify it.)
Before I got the Dell U4025QW I used the LG 40WP95C. I did use it with my MacBook Pro M3Max at the same resolution, 3840x1620 without any problems. I did connect it through the thunderbolt cable. The maximal frequency of the monitor was 72Hz
 
Before I got the Dell U4025QW I used the LG 40WP95C. I did use it with my MacBook Pro M3Max at the same resolution, 3840x1620 without any problems. I did connect it through the thunderbolt cable. The maximal frequency of the monitor was 72Hz
Macbook with m3pro/m3 max doesn't have the issue from this thread. My m3 pro 11/14 running 3840x1620 hdpi on U4021QW without any issue. M3 pro/max macbook pro has Tb4, but m3 ultra has Tb5. My assumptions that this is where the issue (looks like software issue with Tb5 implementation) and this is why I also interested if anybody has a positive expiriens with m3 ultra and 5k2k 40 inch monitor which has 60 Hz refresh rate.

And I am not sure that apple will fix it, but hope. Otherwise I won't upgrade my macbook for long time because monitor upgrade very costly.
 
I wouldn't let this thread deter you from getting a "normal" (16:9) 4K monitor and using it with an M4 mini. A 27", in particular, will look fine to most people even if they work with text all day.

It's not this thread that's deterring me, it's the general state of the market for the type of monitor I'm after.

4k/120, good picture quality, bright, not £1000+ (!!).
 
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I can confirm that the M3 Ultra does not have any issue with LG40WP95C. I have seen posts on Reddit that the 45" LG does not have issues with M4, but I have not tested myself.
I wonder if the reason it doesn’t have any issue is because of the M3 Ultra being an M3 series chip, or because the LG 40WP95C-W is a 72 Hz (i.e., > 60 Hz) monitor? Or both?

Maybe I should go buy an M3 Ultra Mac Studio, test it out with my LG 5K2K (60 Hz), then return it :D

(I can’t afford to keep it)
 
I wonder if the reason it doesn’t have any issue is because of the M3 Ultra being an M3 series chip, or because the LG 40WP95C-W is a 72 Hz (i.e., > 60 Hz) monitor? Or both?

Maybe I should go buy an M3 Ultra Mac Studio, test it out with my LG 5K2K (60 Hz), then return it :D

(I can’t afford to keep it)
It will work with an Ultra.

The monitor needed a virtual display with an M4 Pro. 72Hz is broken too on M4.
 
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OK, so macOS Sequoia 15.4 is out, does it solve the 5K2K 3840x1620 scaled HiDPI issue on M4-based Macs?

<*crickets*>
G'day. And, sorry: no.

Screenshot 2025-04-01 at 9.04.15 am.png


FYI, 75 Hz panel:


Screenshot 2025-04-01 at 9.03.11 am.png
 
I upgraded from Sonoma to Sequoia 15.4 last night, and on my Samsung G95NC superultrawide, running it in 21:9 + 11:9 split still works just fine.

I have the native HDMI port connected and 3840x1620 @ 120 Hz works without issue on my M2 Max MBP 16".
 
I upgraded from Sonoma to Sequoia 15.4 last night, and on my Samsung G95NC superultrawide, running it in 21:9 + 11:9 split still works just fine.

I have the native HDMI port connected and 3840x1620 @ 120 Hz works without issue on my M2 Max MBP 16".

Yeah there is no issue on M2, the issue is on M4

I want to do the exact same setup: but afaik it's not viable on M4
 
I wonder if I should just give up on my LG 5K2K 34” and get something like the new Dell 32” 4K U3225QE that does 120Hz and 3840x2160 so I can get an M4. What would be the default/“ideal” scaled HiDPI equivalent to the 5K2K’s 3840x1620 resolution? 2880x1620?
Assuming by "ideal" you mean having the same icons and text sizes as on an Apple display, I believe the equivalent "ideal" HiDPI resolution for 32" 16:9 displays is 3008x1692.

The 27" iMacs were always 2560x1440, either native or in "default" HiDPI mode. So, being a "stretched" 27" 4K display the "ideal" HiDPI res for the LG 5k2k 34" is 3600x1440. The M4 pro can do 3360x1418, which is not quite there but *very* close. I like more room, so I'm not happy, but I find my LG 34" 5K2K usable even without resorting to BetterDisplay.
 
@Beau Slim I'm not sure I follow your math. This thread has been about M4 Macs no longer supporting the default/"ideal" 3840x1620 scaled HiDPI @60Hz (or below) on Ultrawide monitors. My LG 34" 5K2K is 5120x2160 native and 3/4ths of those two numbers is 3840x1620 so I assumed that the numbers for a regular 4K 3840x2160 would be also be 3/4ths - 2880x1620.

Are you saying your numbers are derived from the Dell's screen size being 32" rather than the pixel dimensions?

In my case I am so used to 2560x1600 (30" Apple Cinema HD Display) that anything less than 1600 vertically in a scaled HiDPI setting is undesirable for me. (Right now I'm on a 2012 Mac mini driving the LG 34" 5K2K at 3840x2160 LoDPI @30Hz. After awhile my eyes start to go a bit haywire given the small type and the low refresh rate.)
 
@Beau Slim I'm not sure I follow your math. This thread has been about M4 Macs no longer supporting the default/"ideal" 3840x1620 scaled HiDPI @60Hz (or below) on Ultrawide monitors. My LG 34" 5K2K is 5120x2160 native and 3/4ths of those two numbers is 3840x1620 so I assumed that the numbers for a regular 4K 3840x2160 would be also be 3/4ths - 2880x1620.

Are you saying your numbers are derived from the Dell's screen size being 32" rather than the pixel dimensions?

In my case I am so used to 2560x1600 (30" Apple Cinema HD Display) that anything less than 1600 vertically in a scaled HiDPI setting is undesirable for me. (Right now I'm on a 2012 Mac mini driving the LG 34" 5K2K at 3840x2160 LoDPI @30Hz. After awhile my eyes start to go a bit haywire given the small type and the low refresh rate.)
34" 5K2K ultrawide is equivalent to a 27" 4K 16:9 screen. 2560x1440 is about right on 27" for scaling, so by that notion the ultrawide scaled res equivalent would be 3413x1440. If you prefer a different scaled resolution, that's your business.

On a 40" 5K2K, which is equivalent to 32" 4K 16:9, you would want a higher scaled res as the display is larger. 3840x1620 is pretty good on for that, though you could make an argument for 4096x1728 (125%) or 4267x1800 (120% scale). The 16:9 equivalents would be 3072x1728, 3200x1800.

The real issue is that MacOS is a total turd when it comes to HiDPI scaling and simply refuses to support this stuff.
 
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Are you saying your numbers are derived from the Dell's screen size being 32" rather than the pixel dimensions?
Yes. Numbers aside, my point was that (being a small ultrawide) the 34" LG we have isn't absolutely horrible with an M4 Pro. If you were getting an M4 pro chip machine anyway, maybe give it a try before getting the Dell monitor.

I didn't know the 2012 mini could do 4K@30. That might be useful!
 
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