[nihonium]

To anyone has a slightly older Mac and thinking about getting a 4k screen: DON'T.

4k is not supported on many older models. Check your official specs. Most Macs has max 1440p@60hz output. 4k is only supported @ 30hz, which is no good for daily usage. And the main problem is, if you get a 4k monitor( to future proof your setup), and try to use it at 1440p, everything will be blurry and pixels will shift and distort.

Just get a native 1440p monitor.

If you have a never Mac, getting a 4k 27" monitor may still be a bad idea. Since 4k is too much for a 27" screen, you will need to use scaling in Mac options, and ideally set it to "looks like 1440p" But this will cause your mac to do 1.5 scaling and create a burden in your GPU and CPU. It will render everything doubled at 5k and try to scale it to 4k. If you're using a Macbook, your fans will never stop even on idle. This is even worse performance than getting a 5k monitor and using it native 2x scaled, which is easy on GPU.

One side note; there is no USB-C Hub that offer 4k@60hz output, technically not possible. You have to get a separate hdmi or dp adapter, or an expensive Thunderbolt 3 dock. But there are some usb-c to hdmi or dp adapters which also offers Power Delivery.

I've already wasted money and time figuring this out, so you don't have to :)

[proverbialbunny]

I have a 2015 MBP that runs 4k60 just fine, but I do admit the gpu gets nearly maxed out on the desktop running software like CLion, as the IDE is gpu accelerated. Anything pre 2015 is most likely a no go.

From a pragmatic standpoint you'll need a gpu that supports display port 1.2 or hdmi 2.0 or thunderbold / usb-c, and at least 1GB of vram as many operating systems take up to roughly 900MB of vram to run a desktop at 4k. Firefox and Chrome can run fine on 100MB of vram (even Youtube at full 60fps at 100MB of vram is fine), but they really want around 500MB of vram to breath, so 2GB is a good safe minimum for having a lot of windows open at 4k.

The 2015 MBP has 2GB of vram and supports display port 1.2.

[saurik]

> One side note; there is no USB-C Hub that offer 4k@60hz output, technically not possible.

This is not correct: there is enough bandwidth for 4k@60hz, just not if you also want USB 3 speeds on the USB hub (which I have no need for: USB 2 is plenty fast enough). I am using a CalDigit USB-C hub with my 12" MacBook (which does not have Thunderbolt) with a special version of the firmware (you have to ask their customer support for a copy) that drops the USB ports down to USB 2 so I can connect to a 4k display at 60hz, and it works great.

[crooked-v]

> If you're using a Macbook, your fans will never stop even on idle.

I have a 2017 MacBook Pro that runs 4K-at-looks-like-1440p fine with no fan noise and without even turning on the dedicated GPU for normal web browser / code editor / document stuff.

[nihonium]

Macbooks always turns on dedicated GPU when connected to an external monitor. Maybe you're using it in clamshell mode?

[mnm1]

MacBook Pros since at least late 2013 support 4k @ 60hz. That's a seven year old laptop. I've been using 4k displays with mine for years with no issues, both at native and scaled resolutions without taxing the cpu/gpu. I would highly recommend it. Your info might apply to other models but definitely not the last seven years of mbpros.

[closetohome]

I encountered most of these issues, with the additional one that some games would force themselves into 3840x2160 regardless of scaling, and then run terribly.

Eventually I just bought a ~2008 30" Cinema Display and have been incredibly happy with it.

[nihonium]

30" Cinema Display is a joy. I used to have one but such a shame that it runs too hot. Living in the UK and working in an office with bad AC, it melted my face :) I let it go.

To anyone planning to use a 30" CinemaDisplay , you will probably need a special Mini DP to Double Dvi active powered adapter. They are not very common so they are a bit expensive. Search for: Tripp Lite Mini DisplayPort to DVI Adapter Cable with Dual-Link Active USB Power MDP to DVI-D, 6 in. (P137-06N-DVI-DL)