How to choose the correct resolution for a 5K2K monitor on macOS? I just bought a LG 34wk95u, an ultra-wide 34” monitor with 5120x2160 native resolution (named 5K2K).
I connected my MBP 13” 2018 to it with thunderbolt.

Please correct me if I’m wrong, but the only way to have the maximum display quality on this kind of monitor, if to have :


1:1 resolution (5120x2160) -> native resolution
or 1:2 resolution (2560x1080) -> because every pixel is x2 horizontally and x2 vertically, so the scaling is perfect.


As soon as we try other resolution, scaling can not be perfect, and text will be a little more blurry (this can be verified running a 4K video on the monitor, pausing on some text). Plus, as stated in macOS display settings: "scaled resolution may affect performances"

The thing is, with 1:1 resolution, everything is way too small on screen, I can't read text. But with 1:2 resolution, everything is too big (et I don’t have enough space on my desktop, 34” becomes useless).

If I change font sizes, I can notice 2 issues:


I need to do it on every software (complicated).
If I take my mac with me to work in a coffee, or just in my bed, font sizes will be wrong on the MBP retina display.


I don’t know what to do.


Should I keep 5120x2160 res but increase font size is every software?
 Should I use 2560x1080 res and decrease font size in every software?
Should I use 3360x1417 res, having a normal size for everything, but
accept that the display quality is lower that it should be? (at
1100€, it hurts…)
 Should I change of monitor and take one with a lower native
resolution?


I'll use this monitor as a software developper who wants lots of real estate to display in the same time: code, terminal, web browser, debuguer.

Thanks for sharing your experience.
Try the 3360 x 1417 scaling mode for a while. That's exactly why it was introduced to macOS as an option -- so that HiDPI displays can actually be made usable instead of having everything tiny. No it won't be perfect, but there's no perfect answer here. After doing your regular workflow for a few days, you'll know if this mode is acceptable to you.



For desktop use, most people are comfortable when the apparent display resolution is around 100 to 110 ppi. People with lower visual acuity tend to prefer a lower resolution around 80-90 ppi.

You purchased a display with a native ppi of 164 ppi, which is much too high to be comfortable. The most performant scaling mode is 2:1 which would give you a ppi of 82, which is too small to be comfortable for most people.

Next time you find yourself purchasing a display, try to find something around 200-220 ppi (looks like 100-110 ppi at 2:1 scaling). Because your laptop has a limit on how many pixels it can push, that means you're looking at a maximum diagonal size of around 29" (at 5K) to get the picture quality you're looking for.