M1 with LG 5K (27MD5KA-B)

[jacol]

Hi,

can anyone, having mentioned devices at hand, please confirm whether M1 macs work (support all features - full 5k resolution, usb-c hub, webcam ...) with a previous version of LG 5K Ultrafine display (27MD5KA-B)?

Thanks.

 

[badsimian]

LG 5K with MBA

When hooked up to the M1 MBA my LG 5K thinks the default resolution for the display is "Looks like 2048 x 1152" instead of the 2560 x 1440 it should be....when I alt-click on the Scaled button then the top resolution it comes back with is 4096 x 2304 (double the aforementioned looks like...

forums.macrumors.com

 

[strangeengine]

My UltraFine 5K is working beautifully with my M1 MBP.

 

[badsimian]

If you go to About this Mac though what does it say? Mine looks like this:-

 

[badsimian]

Okay there is a thread on this. It looks like it is a little twitchy, often get stuck in 4K and you have to switch the cable into the other port a couple of times. I am back at proper 5K now.

LG UltraFine 5K - Owners Thread

It may be that while the M1 Macs can only support 1 display via Thunderbolt, it might actually have two DisplayPort connections to support 5K on the LG UltraFine 5K and also dual cable displays like the Dell UP2715K and HP Z27q. The LG display doesn't have an onscreen menu to see verify the...

forums.macrumors.com

 

[BobHinden]

I have the LG 5K display on my 13" MacBook Pro (2018). I get 5120 x 2880 there. See attached.

Can the M1 do that?

 

[strangeengine]

I have the LG 5K display on my 13" MacBook Pro (2018). I get 5120 x 2880 there. See attached.

Can the M1 do that?

Yes.

 

[nativeneil]

Anyone managed to reliably fix this? I've got an M1 MacBook Air and the LG Ultrafine 5K 27MD5KA (1st Gen) running 11.0.1 but only displaying as 4k. Multiple reboots and port switches but can't get it to recognise 5k. Also the LG Screen Manager doesn't recognise the monitor.

 

[strangeengine]

Anyone managed to reliably fix this? I've got an M1 MacBook Air and the LG Ultrafine 5K 27MD5KA (1st Gen) running 11.0.1 but only displaying as 4k. Multiple reboots and port switches but can't get it to recognise 5k. Also the LG Screen Manager doesn't recognise the monitor.

Mine comes up in 5K correctly but LG Screen Manager also doesn't see it.

 

[strangeengine]

Mine comes up in 5K correctly but LG Screen Manager also doesn't see it.

Now this thread has cursed me - my monitor has started coming up in 4K as well.

 

[strangeengine]

I filed a bug in Feedback Assistant for 11.1 PB.

 

[mcvaughan]

I have the LG 5K display on my 13" MacBook Pro (2018). I get 5120 x 2880 there. See attached.

Can the M1 do that?


View attachment 1677823

Yes, no problem with my MBP and my LG 5K Ultrafine.

 

[dieselm]

I had a similar issue. it's probably your cable.

An official apple thunderbolt cable will connect in 5K. A "lesser" usb-c cable connects in 4k. I'm not clear why it even works at all. The first gen LG Ultrafines don't support USB-c display output like the 2nd gen do (like for the iPad).

 

[strangeengine]

I had a similar issue. it's probably your cable.

I'm using a brand-new $129 Apple Thunderbolt3 Pro 2m cable. It's not the cable.

 

[nativeneil]

I've tried a few cables without success and never had it display as 5k. There is a bug. I wonder if when you change it to run at 2560 x 1440 if that is true retina or if everything is a little off...

 

[arfung]

Hi,

I had issue in which my M1 MBP would only connect to LG 5k ultra fine with 4k resolution. My problem was the cable. TB3 cables actually come in 20Gbps and 40 Gbps. My 20Gbps cable would only drive the monitor at 4k, and when I used a 40 Gbps cable, I could drive the monitor at 5k. Go to "About this Mac" -> "System Report" -> "Thunderbolt" and make sure all of the Thunderbolt connections between computer and monitor are running at 40 Gbps. I have a snapshot below - I'm running through a CalDigit Dock.

 

[BobHinden]

I have used my LG 5K display on my M1 MacMini with the cable that came with the monitor and an Apple Thunderbolt 3 cable ($39 on Amazon). I get 5K with either. Currently using the Apple one because it is shorter, not that I think it should make any difference.

 

[joevt]

I've tried a few cables without success and never had it display as 5k. There is a bug. I wonder if when you change it to run at 2560 x 1440 if that is true retina or if everything is a little off...

Check the Thunderbolt section to make sure the display is connected properly like arfung says. It should be:

Link Status 0x2
Speed: Up to 40 Gb/s x1
Current Link Width: 0x2

If there is a problem, then maybe connecting the display to a Thunderbolt dock might help?

 

[badsimian]

i think 11.1 fixed this. I used to have the issue with an expensive active TB3 cable but it works consistently 100% now

 

[toddpeperkorn]

Interesting. I have an M1 MBA and it will only show 2560x1440. Does this mean a problem with the cable, with the monitor, firmware, software, gremlins, or something else?

 

[arfung]

Interesting. I have an M1 MBA and it will only show 2560x1440. Does this mean a problem with the cable, with the monitor, firmware, software, gremlins, or something else?

View attachment 1746043

I think it's your cable. Are you directly connected from M1 MBA - LG5k? or, are you going through some kind of dock. Here is my sysinfo. As you can see, speed through my cable is much higher...

 

[toddpeperkorn]

So that is connecting with the (Amazon) Thunderbolt 3 cable that was included in the box. It was NOT the one that originally shipped with the monitor, as this was a "renewed" monitor from Amazon.

But notice the dramatic difference in the firmware versions.You have firmware version 43.1 and the Link Controller firmware of 1.23.0. My firmware is 9.4 and link controller firmware is 0.14.0.

When I connect using an Apple .8m Thunderbolt 3 cable, it won't' display at all. It won't turn on.

So here's another interesting bit:

I also have a 2018 Mac Mini, and when I connect the LG to THAT using the Apple Cable, it recognizes it at full resolution, etc. So there must be something either in the firmware of the monitor, or in how Big Sur manages graphics with the M1s, that is causing the problem.

Sigh. So do I return it or not? I'm running out of ideas on how to resolve this. There is no way to get a firmware update, from LG, and I can't find anything at Apple support about the problem.

 

[arfung]

That is indeed strange. Is your 2018 mini running same version of MacOS as MBA? I think it should work with the Apple .8m TB3 cable for both. Have you tried shutting down and then powering up the MBA and then connecting to different ports (I'm reaching here, but maybe one port is bad?)

 

[joevt]

View attachment 1746137
So that is connecting with the (Amazon) Thunderbolt 3 cable that was included in the box. It was NOT the one that originally shipped with the monitor, as this was a "renewed" monitor from Amazon.

Only one of the lanes is working (link width x1) so you're only getting 20 Gbps instead of 40 Gbps. Maybe the cable is broken.

But notice the dramatic difference in the firmware versions.You have firmware version 43.1 and the Link Controller firmware of 1.23.0. My firmware is 9.4 and link controller firmware is 0.14.0.

You have a 27MD5KA. Maybe arfung has the second version 27MD5KB which uses a different Thunderbolt controller. Notice his Thunderbolt Device ID is different.

When I connect using an Apple .8m Thunderbolt 3 cable, it won't' display at all. It won't turn on.

What does the Thunderbolt info show in that case? Maybe the cable isn't broken. Maybe the Thunderbolt port of the display is broken.

I also have a 2018 Mac Mini, and when I connect the LG to THAT using the Apple Cable, it recognizes it at full resolution, etc. So there must be something either in the firmware of the monitor, or in how Big Sur manages graphics with the M1s, that is causing the problem.

Maybe there is a problem with the M1 Mac then. You tried both Thunderbolt ports? You tried all orientations of the USB-C connectors (flip them upside down - two orientations per end, four total per cable).

Sigh. So do I return it or not? I'm running out of ideas on how to resolve this. There is no way to get a firmware update, from LG, and I can't find anything at Apple support about the problem.

Do you have a Thunderbolt dock you can try to connect the LG to?

 

[toddpeperkorn]

Only one of the lanes is working (link width x1) so you're only getting 20 Gbps instead of 40 Gbps. Maybe the cable is broken.


You have a 27MD5KA. Maybe arfung has the second version 27MD5KB which uses a different Thunderbolt controller. Notice his Thunderbolt Device ID is different.


What does the Thunderbolt info show in that case? Maybe the cable isn't broken. Maybe the Thunderbolt port of the display is broken.


Maybe there is a problem with the M1 Mac then. You tried both Thunderbolt ports? You tried all orientations of the USB-C connectors (flip them upside down - two orientations per end, four total per cable).


Do you have a Thunderbolt dock you can try to connect the LG to?

I spent a lot of time with Apple yesterday on the phone, talking to a senior engineer. He is as baffled as I/we are. They are spending the next several days researching, and then we have a scheduled call for next Wednesday. In the meantime, I'm going to try on Monday to go through LG's tech support and see if I can find out another answer there.