Please recommend a USB-C monitor
December 8, 2020 9:12 AM   Subscribe

I need to get a monitor for my new 13-inch Macbook Pro. In the past when using most monitors with my retina-screen laptop there is always a subtle pixelization on the screen which bothers me (I am a designer/using this work). None of the review sites or shopping filters use the terminology I would be looking for (either retina display or 200dpi) What kind of specs should I be looking for in my new monitor to make sure that's not what I wind up buying?

I'm looking at the various review sites which throw around a lot of big numbers that I don't know what they mean, and I can't tell if the reviewers know that I care about whether or not the screen is pixelated, because in the past no one cared about that, so maybe they still don't, I don't know.

I would prefer it to be a USB-C monitor so I don't have to deal with laggy adapters.
posted by bleep to Computers & Internet (10 answers total) 3 users marked this as a favorite
You can calculate approximate PPI given the dimensions of the display, and the resolution. For example, the display I use is 27” diagonal and 16:9 aspect ratio, 2560x1440. Wikipedia provides a table of diagonal to w*h conversions so you don’t even have to do any calculations there. Mine is approx 23.6” by 13.4”, and dividing 1440 vertical px into that 13.7” height gives about 107 ppi, so it wouldn’t meet your spec.

One thing you don’t consider is that “retina” is really about cycles per degree, so 200ppi is only the magic distance at a certain distance. You can use some trig to calculate the actual PPI you need for imperceptible pixels based on how far you want to sit from your display.

You probably don’t need to insist on USB-C — I believe DisplayPort-over-USB-C is supported by contemporary Macs, and converting in a dongle should be seamless.
posted by Alterscape at 9:27 AM on December 8, 2020 [3 favorites]

You can calculate the PPI of the display. In the particular case of this display (noting this is not a recommendation - I've never used the display), you can see that the resolution is 5120 x 2880 and you can see here that the display dimensions are 24.6" x 14.8". Hence, there are (5120/24.6 = 208) ppi in the width dimension and (2880/14.8 = 194) ppi in the height dimension. This is a bit inaccurate because the calculations include the display bezel, but fortunately most monitors have a relatively small bezel.

Note, there's nothing really special about the 200ppi number, despite Apple's claims. Your perception of pixelation is a function of both the number of pixels on the display and how far you are away from the display. As an example, you might not notice the pixels on a Jumbotron stadium display from across the entire stadium even if the Jumbotron pixels are several inches large. You can use this calculator to determine the optimal viewing distance to achieve retinal resolution. For instance, with a typical 27" monitor with 4K resolution, most people will perceive retinal resolution with a viewing distance of about 2 feet. I can attest to this, as I am looking at a 27" 4K monitor from a distance of 2 feet right now :)

I would prefer it to be a USB-C monitor so I don't have to deal with laggy adapters.

USB-C does not imply anything about lagginess, and adapters are not necessarily laggy. You probably don't want to use a USB-C display adapter that only supports 30 Hz operation (like this one), but a (direct) USB-C monitor will have essentially the same latency as an HDMI monitor as a DisplayPort monitor as a Thunderbolt monitor.

(source - part of my job is evaluation and design of custom displays)
posted by saeculorum at 9:29 AM on December 8, 2020 [4 favorites]

For monitors, Rtings is a good resource for reviews and specs. They break out monitors by use case, including a guide for graphic design.
posted by bluloo at 9:45 AM on December 8, 2020 [1 favorite]

If you really want to maximize display performance, don't get a USB-C monitor, get a monitor that supports Thunderbolt 3 (or USB4, which subsumes Thunderbolt 3, if any such monitors currently exist, which I doubt—the M1 Macs support USB4) . This is confusing, because USB-C and Thunderbolt 3 use identical physical connections, but Tbolt supports more Gbps, so you could have, say, two 4K monitors running at 60 Hz, or a 5K monitor at 60 Hz.

That said, my wife has a 4K monitor connected over USB-C to her MacBook Air, and has no complaints, and from peeking over her shoulder, I'd say it looks great.
posted by adamrice at 9:55 AM on December 8, 2020

I use a 30" 4K monitor and I have to look at it real close to see pixelation - any 4k monitor of the same size will be about as pixelly looking. Though if I'm watching a 1080p content on it, (e.g., the new Animaniacs), I see the pixels there of course. A smaller 4K monitor would have even harder to see pixels.

I connected my monitor via a displayport cable, via a dock which is great because it charges and gives me some old-style USB ports if I want to plug in a mouse or memory stick or whatever. I never noticed any display lag, but to be sure, I set my mac to "mirror" and took a picture of a stopwatch. That's a 1/120s exposure, and both both screens have remnants of the previous frame, so I think I'm seeing the difference between how two different LCD panels handle transitions more than anything else.

If you want I can take a super macro photo of the screen but that won't be very helpful - you'll be able to see the individual subpixels, and if you compared it to a comparable photo of the built-in retina display, they'll be bigger (because 3840 / 30" is less than 3072 / 16"), but also I sit further from the external monitor, which to me is one of the points of having one
posted by aubilenon at 9:57 AM on December 8, 2020

Actually thinking some more: If you've experienced external displays feeling laggy or sluggish I can think of two likely culprits:

1) If you're using an adaptor or cable or version of HDMI that doesn't support full 60fps, dragging stuff around with a mouse at 30fps totally feels noticeably worse.
2) SOME televisions introduce a bunch of latency (I don't understand why), but this is not really an issue for monitors. Buy something labeled as a monitor, not as a TV if you care about this stuff, though. (Buy something labeled as a TV if you want to have good colors and contrast from off-center viewing angles though)
posted by aubilenon at 10:09 AM on December 8, 2020

Here at the fruit company, we use 5K LG UltraFine displays. Well, I guess these days you might get one of our Pro Display XDR things, but I was given two of the LGs when I last had my displays upgraded.

The LGs aren't cheap at $1.2k, but they really look great.

But what you want to look for is "5K". I have a high end gaming display I bought in April (4k, 27". GSync, bunch of other fancy gaming stuff I have no idea about since this is my first Windows machine in like 15 years) on my desk, and when I plug it my Mac Book Pro into it, the result is just this side of "eyes start bleeding". In fairness, the result is almost as bad when I plug my gaming rig into the LG.

"Horses for Courses" and all that, and you course requires a "horse" that is 5K.
posted by sideshow at 10:10 AM on December 8, 2020 [1 favorite]

Seconding the LG 5K display. It connects over Thunderbolt 3 to your laptop — this looks like a USB-C connection. They also make a 4K display, which is a less expensive option. Both displays have a built-in camera, microphone, and speakers to do videoconferencing.
posted by They sucked his brains out! at 11:08 AM on December 8, 2020

I recently got the HP Z27 (recommended by Wirecutter's 4K monitor guide) for use with my MacBook and have been very happy with it. It connects to the MacBook with a single USB-C cable which caries the video as well as power for the laptop, and lets you use the monitor as a USB hub. It looks like that particular model isn't available from HP anymore, but it is still available from Walmart. It supports effective resolutions from 1290x1080 to 3840x2160, and has been working great for me. I run it at 3008x1692 and don't find pixels to be visible at all. It doesn't have built-in camera or speakers like the LG, but it's also a good bit cheaper. I'd guess that any of the Wirecutter 4K monitor picks would work well.
posted by duien at 2:12 PM on December 9, 2020

In case it's the cause, don't mirror your laptop display to the monitor. They have different resolutions, and one of them will not be displaying its full native resolution and you'll see scaling artifacts. Either run both displays independently or close your laptop and use an external keyboard and mouse.
posted by How much is that froggie in the window at 1:07 AM on December 10, 2020

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