Why I RETURNED my 4k Monitor // MacOS Scaling Explained!

I recently bought a super nice 4K monitor...and then returned it for the lower resolution 1440p version, why?
I also take a few minutes too explain MacOS scaling on external monitors!

Article about MacOS Scaling
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Intro 00:00
How I got the 4K monitor 00:50
Mac Scaling Deep Dive 02:10
Destroying my RAM 06:00
Deciding to DOWNGRADE 07:30
Why APPLE uses the resolutions that they do 10:30
Conclusion 11:40
Outro 13:53

[ryejack]

Wow, I wish more youtubers would do videos breaking down issues like this in such a good way. That made perfect sense to me and was an issue I didn't even know to look out for until now. Thanks!

[aranykai]

To be more precise, your system is not scaling up anything. It's rendering natively at 5k, exactly as it would be if you were using a 5k display. Integer scaling that down to 1440p is trivial and not causing your issue. You were effectively rendering blender at 5k and expecting it to run like 1080p.

[terryward]

You video adresses exactly the dilemma I was facing. I need a 27" external monitor for my MacBook Air. I had a 1080p Samsung monitor but the scaling drove me nuts. I was going to get a 27" LG monitor as an upgrade but I was told the scaling would still be a problem. The sales associate suggested a 1440 monitor so I started researching and this is what brought me to your article. You have done an awesome job covering the details. In the future you might was to make a long form video on this exact subject aimed at new content creators and do a deep dive so that it can be used as a reference on the subject. Well done...

[jdelgadocr]

Thanks to Hunter for making this video. I wanted a 4K monitor but now I don't want any performance issues. After reading a bunch of comments here and its replies it seems there are two actions that may provide some solution:

1-Make sure the resolution in System Preferences is set to "Default for display" (otherwise set it that way, close and reopen System Pref), then hold down OPTION key while clicking the SCALED option, now it should show more options in the list. For a 4K monitor, choose the 5K resolution (5120*2880). This should enable the real Retina scaling but the monitor will only display what it can. Now check if the performance is affected or not.

2-the other option is to use the Betterdummy (Betterdisplay) utility to adjust and enable the HiDPI (Retina) scaling that is not enabled with some 4K monitors.

Also, if you are using a MacBook (not a Mini or any other desktop model) try closing the lid so the built in display will go OFF and the whole GPU will be dedicated to the external monitor(s).

Can somebody with a 4K monitor (and having issues) try these and post the findings and monitor model here??

[keephunnid]

Bro this video is gold. I have been looking into monitors trying to decide what ppi to get and none of the resources gave a proper reasoning for their suggestions except your video. Thank you

[robertd]

Dude.. this is one of the best videos on Mac monitors and resolution I've seen. Fantastic research man. Thanks for throwing this up.

[boredandagitated]

I knew how retina worked but I never thought about the gpu rendering issue you talked about. A really small 4K screen like 24” would prolly be awesome. But I love my 27” 1440p so my next upgrade will be for a 5k monitor so I can go retina resolutions on my desktop. That crisp text is my favorite thing on the MacBook screens

[michaeldangelomusic]

Thank you so much for this video. I had been running an LG 4K 27" monitor with my MacBook Pro for about 2 years and while I didn't have performance issues, I had significant overheating issues. Simple tasks like watching YouTube videos or word processing would kick the fans on full speed. Your explanation of how MacOS handles display scaling is spot on and I finally figured out the issue to be running in scaled mode and the computer essentially sending out a 5K/6K signal and downscaling to 4K, significantly taxing the GPU on my machine.

I wound up purchasing the same ASUS ProArt 27" 1440p monitor you talk about here and I'm happy to say there are absolutely no performance/overheating issues and the display looks great. I will miss the retina aspect, but I'd rather take that than dealing with a hot, slow computer. Thanks again, Hunter!

[curtiskupferschmid]

Sounds like a lot of folks have the same issue. I just want to add for those who are really worried about this: I’ve used a 27” 4k display for a year at 1080p scaling (default) with no problems. The text is sharp and not too big at all. MacMost has a video about why you shouldn’t buy a 1440 monitor where he discusses scaling really well. I recommend watching that video too because together with this one you’ll be able to figure out what the right choice is for you.

[nav]

I love using my 4k monitor on my M1 MacBook Pro. The performance is buttery smooth. But I’m not doing 3D rendering - I’m using it for my software development workflow.

Sounds like this won’t be an issue for most users.

[josephholmes]

I had another thought. I've been working at the scaling issue with a friend for a long time now and I think we've figured out something important regarding what you observed for the slowdown with the 4K monitor. The original theory being that it was all the work to constantly upscale and downscale frames 60X each second. Now it appears as though that's not it at all -- rather it's just a shortage of RAM. Your 13" M1 MacBook comes with either 8 or 16 Gigs of shared memory. I don't think you mentioned which one you got, but certainly all Macs start to slow down as they come close to running short. You can see how they operate if you open Activity Monitor and examine the use of compressed memory for the many running applications, and the residual free memory (in particular, among various other memory measurements). Once you see a lot of apps running with some of their data in RAM having been compressed (that portion gets compressed down to about 40 to 50% of its original size when that's happening, so it frees up more RAM) you can be sure the OS is having to work harder to keep the ball rolling. I find that when my 16 GB 2012 MacBook Pro is down to less than 2 GB "free" it's starting to get complicated and may get very slow, and if it's down to 1 GB free I'm really in trouble and the machine is very prone to becoming highly unresponsive, but intermittently, in a complex pattern.
So what we did, my friend used his 2021 14" MacBook Pro M1 Max with 64 GB of RAM to run an experiment I suggested. He's got it connected to a 31.5", 4K NEC display, so it's VRAM requirement (the GPU's share of the shared memory of the SoC Mac) is essentially the same as your 4K ASUS's was. There is a feature in Activity Monitor called "Memory History" that opens a little window and creates a running bar graph of GPU activity. If you just open that little window then do some things like open a new window or scale something or whatever, you can see how much your GPU cores are working as a result. He opened up a 4K video and played it. He changed the scaling of the screen in the Displays system pref, and there was a huge spike in GPU utilization that lasted a fraction of a second, but then it fell back essentially to zero. I.e. it jumped from showing only one tiny square to around 40 tiny squares tall of utilization for just two columns of squares. Same for switching back to the other scaling option. This test shows rather conclusively that the GPU does not have to labor continuously on account of using a different scaling from the "Default", or if it does that that labor is tiny. On the other hand, we do know that gamers using a 4K display with an 8 GB discreet GPU do run into trouble with performance in some degree with some games and some frame rates. So I'm betting that your performance problem had its actual root in a shortage of RAM. E.g. the CPUs or the GPU cores, either one or both, may have been starved for memory to the point of messing with your other program. For me, this is a huge deal, that it's OK to use the scaling options without constantly burdening the GPU and wasting power too, because it means I have about 10 monitors to choose from instead of 2! (all of which are pretty good candidates, but none of which are perfect -- is there such a thing? I'd prefer to see more 5K 27" and 32" displays and/or to see macOS stop scaling user bitmaps whenever native or half native scaling are not being used. Thanks for helping work this out. More science! :-)

[silentdrive]

This was hands-down the best layman's perfectly broken down description of this issue. Well done man. I don't even think like Linus Tech tips or any of those guys ever broke this down this way. Awesome!

[DanielFNG]

Nice summary of this issue. Only thing I would say is that, at least in my opinion, the difference in text clarity between 27 1440p and 27 4k is very noticeable on Mac. I'm currently running a 1440p display for gaming and a 4k display largely for content consumption or software development, which is much of my day job. Admittedly though I don't really use GPU intensive programs on my 4k monitor so I've never run in to the performance issues you mention.

[agentfifteen]

Every resolution has a non-retina variant, so for example, you'll have a 2560x1440 retina version and also a 2560x1440 non-retina version which won't influence performance at all. To see all resolutions, in display settings right click and click on show list and you'll get a huge list of resolutions and to see the non-retina options turn on "show all resolutions" at the bottom. I guess you were unaware of that.

[ieattunaeveryday]

Hey, Hunter. Thanks for this very in-depth video!
I have a small Macbook Air M1.
I'm a writer, so I need text to show up as clearly as possible--as I'm constantly staring at text.
I've read some comments that text actually shows up better on 4k displays...
What was your experience with how the text showed up on 4k vs 1440p displays?
Thanks!

[british]

@Hunter King BTW, if you option click on "scaled" you will get resolution by the numbers AND you get a "Show all resolutions" button that will tell you which resolutions are scaled or processor intensive. Pretty much answered some of the questions you had about what resolution works best. Agreed about most of the information you presented tho.

[josephholmes]

Very well done. Thorough and correct coverage of most of the issues. The one that you hadn't noticed yet is that when the scaling option chosen in the Displays system pref is neither the screen's native ppi (3840 wide) or 50% of that (1920), macOS scales Photoshop bitmaps using bilinear interpolation, causing all visible pixels to be degraded and hiding their true character. This messes with the process of working out optimal sharpening. What we need for that is to have all bitmap user images to be shown as one image pixel per screen pixel when we're zoomed to "100%". And sadly, in macOS, that's only possible when we're using one of those scalings: native or half native. So it doesn't <exactly> mean that screens outside of the two green zones in the good reference you cited can't work, but if a screen is outside of the green zones, then you'll be forced to choose a scaling that either makes everything much too big (e.g. ~40% too big) or much too small (~30% too small), but those percentages vary with the choice of 27" 4K or 32" 4K. One might be forced to constantly flip back and forth between scalings, and/or mess with lots of settings for font sizes and so on, but this is a major shortcoming of macOS which has been revealed by the industry trend toward 140 and 164 ppi screens, which are otherwise quite nice. Since there are only 2 5K screens at 27" in the world and only the one 6K 32" screen, we're left with way too few choices. All three of those screens have significant shortcomings but the 27" Studio Display's may be the least bothersome. Perhaps it's worst feature is that it cannot be connected to any machine except a very new one, and among Macs it requires both a new Mac and one of the latest OS's. It's color gamut is a solid, full P3 gamut, its two screen surface options are each good-looking, and it has high max brightness, and so on. This business of monitor shopping has become quite the nightmare of complexity, if you're after the best for each feature.

[xuchenglin]

This is called “HiDPI” or retina mode, 4 pixels represent 1 pixel so you get perfect scaling. 4k to 1080p and 5k to 1440p. Actually in my preference I found the 4k 27’ monitor at “looks like 1080” default option is better than the 5k iMac at “looks like 1440p” default. The distance also matters. What kind of work you do also matters. As of the scaling artifacts/performance dropping, after a long time you won’t notice/bother this anymore. Most of softwares have scaling options inside, no matter what screen you use, you simply scale to your preference. So the OS scaling only affects the menus and bars and non-scalable UI elements. Now I constantly changes the scaling factor to meet my own need. Instead of stick to the perfect “retina” scaling forever and telling myself that is the best, now when I browse the web or write something, I will even use the largest setting in 5k iMac, the larger text just makes everything easier. When I do multiple window things like tweaking some techy thing, I use the smallest looking scale and don’t bother with “potential performance dropping and artifacts” anymore. I encourage you to try to just get used to the 1080p looking UI if you are GPU limited, it not so big a thing after you don’t take it seriously.

[hanuman]

This helped me so much, thanks. I had been looking at 4K's for my new MB Pro M1 Pro. Great energy, Hunter.

[JakeBibler]

Dude, this was exactly what I was looking for… I have the same MBP and I’m trying to decide which monitor to purchase as a replacement for my old dual 23” desktop setup. You just saved me $100 and probably a headache. Thanks!