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LG UltraFine 5K - Owners Thread
- Thread starter iBrooker
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Nice.
But then you unplug the MBP, and all the windows randomise themselves across the MBP screen. Can be a pain.
Then you come back home again, plug in, to find things all over the place. Going from 'several big screens to small screen and back to several big screens' again, is still a difficult thing to make work without annoyance.
EDIT: And we still can't plug two LG 5K's into one TB4 port can we, AFAIUI? Even though the new MBPs go from 2 buses to 3 buses.
An LG UltraFine 5K requires two DisplayPort 1.2 connections over Thunderbolt (two tiles of 2560x2880 at 483.37MHz). Each connection is 14.5 Gbps. There's no way you could connect two of them to a single Thunderbolt port - that would require 58 Gbps but Thunderbolt can only do 40 Gbps.
There exist 5K displays (e.g. iiyama ProLite XB2779QQS-S1) that take a single DisplayPort 1.4 signal at 967.01MHz but only up to 8bpc. Each display requires 23.2 Gbps so two of them cannot be connected to a single Thunderbolt port.
The XDR display uses DSC which compresses the video signal to ≈12bpp so its 1286.01MHz pixels only requires 15.4 Gbps. You can connect two of those to a single Thunderbolt port.
It should be possible to create an adapter that takes a DSC signal like the one used by the XDR and output two DisplayPort signals for a dual tile display like the LG UltraFine 5K (or the Dell UP3218K or the LG 5K2K display or the Acer XV2713K, etc.). With such an adapter, the LG UltraFine 5K would only require 11.6 Gbps. The LG UltraFine 5K is a Thunderbolt display, so the two generated DisplayPort signals need to be converted to Thunderbolt. That can be done with a Thunderbolt 3 add-in card.
The proposed adapter would be like a video wall processor. It takes one input and divides it between multiple displays. However, I haven't seen one that does DisplayPort 1.4 or DSC. https://www.matrox.com/en/video/products/gxm/dualhead2go-series/digital-me
I suppose it could be made with a sufficiently powerful FPGA that can do DisplayPort 1.4 HBR3 + DSC input and dual outputs but I think they're really expensive?
There may exist some display driver boards that can do the job.
https://forums.macrumors.com/threads/diy-5k-monitor-success.2253100/
Good tech specs explanation! ;-)
So to summarise what (I think) you're saying:
1. 2 x Apple XDR 6K's can be connected to a single M1 Max MBP port (upto 3 overall per MBP, plus a 4K via HDMI).
But what adapter does two TB3 XDR's from one TB4 port, though?
EDIT: This CalDigit Element TB4 Hub maybe...?
2. LG UF 5K3K's (upto 3) cannot be connected to a single M1 Max MBP port, so has to use separate TB4 ports.
And presumably this is the same for both versions of the LG UF 5K3K: RevA (5K via TB3 only) and RevB (5K via TB3 or USB-C)?
I am guessing that it should be possible to connect two XDRs to the same port and get 6K60 using DSC. Waiting for someone to confirm.
Yes, any Thunderbolt 4 hub or dock. They have three downstream Thunderbolt ports and you can connect two displays to any two of those ports (or two to a single port using another Thunderbolt adapter). Both XDRs connected this way should have full speed USB 3.0 support.
Another option is a Thunderbolt 3 dock like the HP Thunderbolt Dock G2. Connect one display to the USB-C with DisplayPort Alt Mode port (this will only allow USB 2.0 from the XDR) and another display to the downstream Thunderbolt port.
A third option is a Thunderbolt to Dual DisplayPort Adapter. In this case, connect two XDR displays using a Belkin Charge and Sync Cable (both displays will be limited to USB 2.0).
An LG UltraFine 5K display requires two DisplayPort connections so it is unlikely that the M1 Max which can support 4 displays will allow connecting more than two LG UltraFine 5K displays (or one LG UltraFine 5K if the fourth display must come from HDMI port). It would be surprising if the M1 Max had unused DisplayPort connections reserved for dual tiled displays like the LG UltraFine 5K but it would not be unprecedented since that's exactly what the original M1 Macs do.
If you force the LG UltraFine 5K to use a single DisplayPort connection, then you could connect 3 or 4 of them but you would have to limit it to 4K60 or 5K39 using a custom timing but I don't know if the new M1 Macs support custom timings (the old M1 Macs did not).
You already got the 2021 MacBook Pro with 2 Ultrafine 5Ks attached? Thanks for the information, I was looking for real world confirmation that it works.
No the 5K does not have a downstream Thunderbolt port. Do you mean the CalDigit TS3 Plus? That dock uses Alpine Ridge and is therefore only compatible with Thunderbolt. Newer Thunderbolt devices that use Titan Ridge or Goshen Ridge can be connected to the USB ports of the 5K.
The LG UltraFine 5K display uses two DisplayPort 1.2 connections of 2560x2880 to make a 5120x2880 image.
The Alpine Ridge (for first gen LG UltraFine 5K 27MD5KA) or Titan Ridge (for second gen LG UltraFine 5K 27MD5KL) Thunderbolt controller that is used by the LG UltraFine 5K has only one dedicated DisplayPort output. The second DisplayPort output comes from the downstream Thunderbolt port. So that's why the LG UltraFine 5K doesn't have a downstream Thunderbolt port. It's the same with any Thunderbolt dock or adapter with two DisplayPort or HDMI outputs.
Now, if a third generation LG UltraFine 5K display were to be created, it could use a Goshen Ridge Thunderbolt controller. Since Goshen Ridge has three downstream Thunderbolt ports, the fist two can be used for the two DisplayPort connections and the third could be used for downstream Thunderbolt devices. However, it would probably be better for such a display to use DisplayPort 1.4 and DSC instead like the XDR display. For GPUs that don't support DSC, the dual tile method is still useful (which the XDR also does). Then again, the Goshen Ridge is only supported by Big Sur so you might want to go with Titan Ridge with no downstream Thunderbolt port like the XDR.
Thanks! I have decided to connect the MBP Max To the 5k display and then the T3+ to one of the other ports on the MBP Max and then connect my audio interface (Apollo Twin X) to the T3+. It just means two cables instead of one.
Yep, tested with a monitor(1440p) in the HDMI port too, works great.
pics are in the thread.
Oh, I just noticed your pics say two LG UltraFine 5K and a display connected to the HDMI port. That would mean there's 5 DisplayPort connections. So it means the M1 Max is reserving DisplayPort connections for dual tile displays like the original M1 Macs did. And maybe you could connect another display.
Or it could mean that the LG UltraFine 5K displays are not running at 5K. Does SwitchResX show timing info on M1 Macs for the currently selected resolution (double click the resolution to see the timing info)? The timing info could also be in the IORegistry like for the first M1 Macs. I probably have to update my script for the new M1 Macs. https://gist.github.com/joevt/e862b0088ef58b9144877d01401bcee8
Did you try connecting both LG UltraFine 5K displays to the left hand side Thunderbolt ports?
Can you get scaled HiDPI resolutions higher than 3008×1692, such as 3200×1800 or 3360×1890 (try holding Alt/Option while clicking Scaled)? I'm asking because the original M1 is limited to a width of 3008.
Well just for you there I connected both wires on one side and they came on like normal(that was a hassle as the cables are fixed in so I have one each side for the cable management). I did not have the HDMI monitor connected as would need to re wire everything.
They seemed to be working normally as they are now its plugged in one each side. The displays looked normal to my eyes and how they are with my 2016 MBP.
EDIT - tried two one side and then the HDMI and a crash on the computer.
People reported success in another thread with HiDPI modes greater than 3008 width.
https://forums.macrumors.com/threads/m1-mbp-lg-34-inch-ultra-wide-5k2k.2267299/post-30522273
Then that would suggest 4 DisplayPort connections on the left side. Maybe two more on the right side. Plus one for the HDMI would make 7. Seems too good to be true. The limit has not been reached yet. Really need ioreg or timing info to be sure.
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Strange. I would have expected nothing to happen if it wasn't supported. Was there a crash log?
The 5K monitors are connected on opposite sides.
I wonder which display it chooses to charge from. Does the Mac figure out which one has the highest charging capacity and go with that one or is it the first one that is connected.
Is one of the displays connected to the HDMI port? Can you connect all 4 to Thunderbolt ports? can you connect the 5Ks to the left side? Can you post the output of the following command:
Code:
ioreg -fiw0 > ioreg_M1_Max_4_displays.txt-fiw0 to -fliw0 to get all the info now.
