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JeffL99

macrumors newbie
Original poster
Apr 19, 2021
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Which type of monitor would be the most suitable for me? I have recently bought an Apple MacBook Air with the M1 chip with a screen resolution of 2560x1440. I want to use this with a monitor when at home to replace my Apple iMac 21.5” (Late 2012 model) which has a screen resolution of 1920x1080. I need advice on whether I should choose a monitor with 1920x1080 or 2560x1440 or other resolution. I would like a screen size of between say, 22” and 27” and don't want to pay more than I need to. I do not do any gaming, I only use for internet, email, WhatsApp, messages, spreadsheets and letters, all for home use. Thank you.


 
Do you want text to be as crystal-clear and sharp as on the MBA?

If yes, then go for a 4K (UHD aka 3840x2160) IPS monitor. The smaller, the better (due to a higher pixel density). Finding a 4K screen smaller than 27" has become slightly difficult these days though. I use 21.5" 4096x2304 and 23.8" 3840x2160 monitors and they're great.

If you can deal with not-quite-as-sharp text (due to lower pixel density), a 25" or 27" IPS 2560x1440 is a nice size also providing lots of screen estate.

I'd not bother with 1920x1080 anymore. Not enough screen estate IMO. If you're keen on 1920, then go for 1920x1200.
 
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Just a small point - native resolution on the M1 MBAir is 2560 x 1600.
Ah! Quite right, I've obviously been researching too many monitors with 2560x1440 resolution and got mixed up. Thanks for the reminder. So..... is the general consensus that with an MBA of 2560x1600, that a monitor with 2560x1440 with a screen size of 22" to 25" would be a good fit for what I'll be using it for? The ones I've found so far are Dell P2421D, P2421DC, U2520D. BenQ BL2420PT, PD2500Q. Samsung S24H850. Not sure if there is anything to choose between manufacturers regarding quality, reliability etc? Other names to research are Lenovo, Acer, AOC, Asus. I also want something with a solid type stand not the splayed-out (prong type) as they will be a better fit on my desk set-up.
 
If you want anywhere close to the text clarify of the built in display, between 22 and 25", your only practical option these days is the LG UltraFine 4K.

If you can find one of the original UltraFine 4K's (the 21.5" model) used that would be exactly the same clarity.

Alternatively if you can find a used/end-of-stock Dell P2415Q, it's the same size+resolution as the current UltraFine 4K (but a **** load cheaper).

I'm sure someone will tell me "it's not a problem" but I found it hard enough occasionally looking at my pre-retina MBP screen (i.e. ~110 PPI) if my wife needed help with something after I started using a retina MBP, I cannot imagine your eyes/brain will not try to murder each other with spoons if you're constantly using one screen at ~220 PPI (laptop) and one at say 133PPI (2560x1440 @ 25"). Actually it's probably more likely to be a murder-suicide, to put them both out of their misery.
 
So..... is the general consensus that with an MBA of 2560x1600, that a monitor with 2560x1440 with a screen size of 22" to 25" would be a good fit for what I'll be using it for?
The thing is - the MBA runs a scaled setting of "Looks like 1440x900" out of the box, meaning things appear at the size of a hypothetical 13.3" 1440x900 screen but a lot sharper. That results in a simulated pixel density of 127 ppi.

If you want things to be the same size on the external monitor as on the MBA at the same viewing distance, your options providing similar (real or simulated) pixel density are:

- 24" at 2560x1440
- 24" 4K scaled to "looks like 2560x1440"
- 27" 4K scaled to "looks like 3008x1692"

However, as the viewing distance is usually greater for external monitors than for laptops, about 110 ppi (real or simulated) is a good target (and is what eg. the Retina iMacs default to with regards to their "looks like" modes).

That means:

- 27" 2560x1440
- 21.5" 4K (original LG UltraFine) scaled to "looks like 2048x1152"
- 24" 4K scaled to "looks like 2304x1296"
- 27" 4K scaled to "looks like 2560x1440“
 
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If you can find one of the original UltraFine 4K's (the 21.5" model) used that would be exactly the same clarity.
I have that monitor. I run it at the pixel-perfect "looks like 2048x1152" setting.

Alternatively if you can find a used/end-of-stock Dell P2415Q
I have that one too. Running at "looks like 2304x1296".

I'm sure someone will tell me "it's not a problem"
Well, I'm not the one to do that, given my choice of monitors. :) I want at least about 110 ppi (preferably 4K/5K with respective scaling) or else I'm going mad.

To the OP - this is a good and important point, so definitely worth considering, but these two monitors aren't being sold anymore.
 
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A review said it uses PWM. I'd avoid that at all costs. The P2415Q does not.
Huh. I hadn't got that far into it - the price alone makes it hard to buy, given how much cheaper the Dell's were.

OP: the Dell is discontinued, but I still see them listed for sale on several US sites, both new and used. (doesn't help me much here though!)
 
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The thing is - the MBA runs a scaled setting of "Looks like 1440x900" out of the box, meaning things appear at the size of a hypothetical 13.3" 1440x900 screen but a lot sharper. That results in a simulated pixel density of 127 ppi.

If you want things to be the same size on the external monitor as on the MBA at the same viewing distance, your options providing similar (real or simulated) pixel density are:

- 24" at 2560x1440
- 24" 4K scaled to "looks like 2560x1440"
- 27" 4K scaled to "looks like 3008x1692"

However, as the viewing distance is usually greater for external monitors than for laptops, about 110 ppi (real or simulated) is a good target (and is what eg. the Retina iMacs default to with regards to their "looks like" modes).

That means:

- 27" 2560x1440
- 21.5" 4K (original LG UltraFine) scaled to "looks like 2048x1152"
- 24" 4K scaled to "looks like 2304x1296"
- 27" 4K scaled to "looks like 2560x1440“
I want things to look the same size on the new monitor as they do on my existing iMac 21.5" (which I will be retiring when I buy the new monitor). For example the text on the iMac whilst reading this thread is bigger than reading it on the MBAir. I therefore gather I should buy a 27" monitor with 2560x1440 resolution and preferably IPS? Or could get a 25" but text would not be quite as pin sharp? Just checked the spec of my iMac at 102 ppi, so that is what I am used to. So what do you think?
 
Just checked the spec of my iMac at 102 ppi, so that is what I am used to.
Then the closest to that is:

- 21.5" 1920x1080 (same ppi - obviously)
- 24" 4K scaled to 2048x1152 (98 ppi - things will be minimally larger than on the iMac)
- 27" 2560x1440 (109 ppi so things will be smaller than on the iMac) - either native or 4K scaled to that resolution
- 27" 4K scaled to 2304x1296 (98 ppi)

As for IPS - make sure to go IPS and flicker-free (no PWM).

And if you want pin-sharp - you have to go for a 4K, or even higher-res, monitor. Fonts just don't look as good on "non-high-PPI" (eg 2560x1440) monitors in macOS anymore.
 
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And if you want pin-sharp - you have to go for a 4K, or even higher-res, monitor. Fonts just don't look as good on "non-high-PPI" (eg 2560x1440) monitors in macOS anymore.
Agreed.
I'm using a 32" 4K monitor at 'looks like 3008x1692' and it's perfect. I haven't bothered to calculate the DPI, but while it's obviously going to be lower than a 27" 4K, I can barely tell the difference between this and 'looks like 2560x1440' on a 27" 4K display.
 
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