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LG UltraFine 4K and 5K: Yes you can connect it to Windows computers via DP!!!
- Thread starter DeanL
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If you have the older UltraFine 5K (27MD5KA), it only accepts video input via Thunderbolt 3, and there's no easy way to hook up a non-Thunderbolt video source.
If you have the newer UltraFine 5K (27MD5KL), it additionally accepts video input via USB-C, so a HDMI 2.0 to USB-C adapter (like the Club3D CAC-1332) is what you need.
Hi guys,
I have the LG Ultrafine 5K monitor and was trying to research if I could connect my Windows Desktop with a AMD RX580 graphics card with DisplayPort to the LG monitor using a bi-directional DP to USB-C cable? I'm seeing it might not get 5K, but that's fine with me.
On the other hand, I'm reading some people have installed some custom adapters in their desktop, purchased external 'hubs', etc.
Will a simple cable work for my situation?
I have the LG Ultrafine 5K monitor and was trying to research if I could connect my Windows Desktop with a AMD RX580 graphics card with DisplayPort to the LG monitor using a bi-directional DP to USB-C cable? I'm seeing it might not get 5K, but that's fine with me.
On the other hand, I'm reading some people have installed some custom adapters in their desktop, purchased external 'hubs', etc.
Will a simple cable work for my situation?
@joevt @Amethyst1
Hi all,
Share the results because all cables have arrived. The CAC-1334 cable did not function normally.
But the USB-C cable enclosed with LG monitor and SIIG combination worked like a charm.
(Many thanks to all of you.)
However, the default resolution was so low that I corrected the resolution through EDID manipulation with the following script(https://github.com/xzhih/one-key-hidpi). But my eyes hurt so much.
Is there any way to use it without hurting my eyes?
Hi all,
Share the results because all cables have arrived. The CAC-1334 cable did not function normally.
But the USB-C cable enclosed with LG monitor and SIIG combination worked like a charm.
(Many thanks to all of you.)
However, the default resolution was so low that I corrected the resolution through EDID manipulation with the following script(https://github.com/xzhih/one-key-hidpi). But my eyes hurt so much.
Is there any way to use it without hurting my eyes?
If you have the older UltraFine 5K (27MD5KA), it only accepts video input via Thunderbolt 3, and there's no easy way to hook up a non-Thunderbolt video source.
If you have the newer UltraFine 5K (27MD5KL), it additionally accepts video input via USB-C, so a bidirectional DisplayPort to USB-C cable or e.g. the Wacom Link Plus will provide "4K" at 60 Hz.
Are you referring to this one? https://www.siig.com/hdmi-to-usb-c-port-4k-60hz-converter-adapter.html
Do you get USB 2.0 functionality? Are you able to use the USB features of the display such as brightness control, audio, camera, USB ports?
What resolution were you getting before and what resolution are you getting now? (SwitchResX timing info; AllRez; AGDCDiagnose (Intel Macs only); ioreg.pl/M1MacTimings.sh (M1 Macs only))
Current HDMI to DisplayPort adapters are limited to 4K width. Maybe you can get 4096 x 2304? You need the timing to be below 600MHz to get 8bpc RGB (600MHz is the limit for HDMI 2.0 for 8bpc RGB; LG 5K actually has a slightly lower limit so you may need to try 590MHz). I think DisplayPort would get you 10bpc but the difference between 8bpc and 10bpc is not the reason for the ocular pain.
Future HDMI 2.1 to DisplayPort 1.4 adapters will hopefully support 5K width so you can try 5K 39Hz but I already mentioned that in #483
If the UltraFine didn't expand any lower resolution signal to fill the screen regardless of the aspect ratio (my 21.5" 4K does it so presumably the 5K is the same); 4096×2880 at ≈48 Hz might also have been a possibility.
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That would be interesting. Someone give it a try. It would require an Intel Mac. Create a custom timing of 4096x2880 and a scaled mode of 5120x2880. Set the "Scaled resolutions base" option to 4096x2880. This test needs to be done with a non-Thunderbolt 3 connection. Try it with a straight DisplayPort connection (or Thunderbolt 2 connection if you have the old LG 5K model). In the HDMI source case, the adapter needs to be able to support 2880 vertical lines. I don't think I've ever tested that.
Wouldn't this result in a 5120×2880 framebuffer being "squished" onto a 4096×2880 screen? I use 3:2 monitors and selecting any scaled 16:9 mode results in black bars at the top and bottom.
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You're right. I don't have a 5120x2880 display but my 4K display is able to scale down resolutions up to 8K, so I tried a 4096x2880 timing. The display does scale that down to fill the entire 3384x2160. However, there is a problem with the GPU scaling: a 16:9 scaled mode will result in black bars at the top and bottom when output to a more square framebuffer (4096x2880 is like 10:7 which is similar to your 3:2 - the most common more square aspect ratio is 4:3).
I suppose anyone can test this with any display that support arbitrary timings (if your display doesn't scale down, you can use smaller resolutions that scale up such as 3000x2000). Actually, you probably don't need a custom timing. The Displays preferences panel may already have modes with aspect ratios that don't match your display (if you select "Show all resolutions"). For example, My iMac with 16:9 2560x1440 display has 4:3 modes like 1024x768. Such modes will have black bars at the left and right on a 16:9 display.
There doesn't seem to be a simple way to get the GPU to not do the black bars when scaling to the framebuffer when the aspect ratios don't match between the framebuffer size and output timing size (it always assumes the framebuffer pixels are square). Maybe a patch from Lilu/WhateverGreen could be made to give control over that.
Greetings everyone,
Just wanted to post my experience here and thank all of you for the extensive troubleshooting and testing!
I have been enjoying my LG 21.5” 4K for a couple weeks now, along with the suggested Wacom Link Plus.
Unfortunately, I did not take the time to fully read through this thread when looking into the possible options to get the display to work with my Windows PC (with an external GPU) and bought the Moshi USB Type-C to DisplayPort cable first. Only to find out the the 21.5” expects a USB signal to turn on, which my NVIDIA GTX 1080Ti does not provide through the Moshi cable.
Just wanted to post my experience here and thank all of you for the extensive troubleshooting and testing!
I have been enjoying my LG 21.5” 4K for a couple weeks now, along with the suggested Wacom Link Plus.
Unfortunately, I did not take the time to fully read through this thread when looking into the possible options to get the display to work with my Windows PC (with an external GPU) and bought the Moshi USB Type-C to DisplayPort cable first. Only to find out the the 21.5” expects a USB signal to turn on, which my NVIDIA GTX 1080Ti does not provide through the Moshi cable.
Able to successfully connect both my LG UltraFine 5K and 4K displays to my PC, however can't get both working at the same time. Seems to be either one or the other. Any suggestions? Currently have thunderbolt cable going from both to the thunderbolt 4 expansion card that's connected to my graphics card via the supplied Thunderbolt to DisplayPort cable. I can connect a second Thunderbolt to DisplayPort cable to my graphics card, but doesn't seem to change anything
What's a Thunderbolt to DisplayPort cable? Do you mean DisplayPort to Mini DisplayPort cable? If you only connect one of those cables from the GPU to the Thunderbolt 4 add-in card, then you can only connect one display to the add-in card.
If you connect the LG UltraFine 5K to the add-in card first, then it may work at 5K (if both cables are connected). If you connect the LG UltraFine 4K to the add-in card second, then it won't work because the LG UltraFine 5K will have taken up both of the DisplayPort connections that are provided to the add-in card.
If you connect the LG UltraFine 5K to the add-in card second, then it may work at only up to 4K because the LG Ultrafine 4K will be using up one of the DisplayPort connections. In this case, you might be able to get a 5K 39 Hz timing to work (using a custom resolution created by CRU or your GPU software).
What you probably want to do is connect only the LG UltraFine 5K to the add-in card so that it works at 5K 60Hz. Then the LG UltraFine 4K needs to be connected directly to a third DisplayPort output of your GPU using an adapter (Wacom Link Plus or Belkin Charge and Sync cable or similar).
Does anyone have a source for the Club3D CAC-1332? Looking to hook up a PS5/Xbox to an ultrafine. I’ve been looking for one for a few months now and haven’t been able to find them. Is there a newer version coming out?
@joevt
As shown in the image below, the default resolution was 1920 x 1080 and the rest was very blury due to low resoultion.
As I mentioned last time, I'm using the HiDPI configuration script to set the resolution to 2560 x 1440.
Finally, I am attaching the results of running AGDCDiagnose. Could you please check if there is any problem?
Thank you so much for your help as always.
The product is right. Audio, camera, and USB ports are all work fine and only the brightness adjustment software has been installed to adjust it.
First of all, I don't have any knowledge in this area, so I'm sorry for bothering you.
As shown in the image below, the default resolution was 1920 x 1080 and the rest was very blury due to low resoultion.
As I mentioned last time, I'm using the HiDPI configuration script to set the resolution to 2560 x 1440.
Finally, I am attaching the results of running AGDCDiagnose. Could you please check if there is any problem?
Thank you so much for your help as always.
Try the SIIG version of the same adapter? https://www.amazon.com/dp/B08WCNYCQT
Club3D now has a CAC-1333 that doesn't include USB 2.0. Sad.
https://club-3d.com/en/detail/2573/hdmi_to_usb_type_c_4k60hz_active_adapter_m-f/
Compare with the CAC-1332:
https://club-3d.com/en/detail/2517/hdmi_to_usb_c_4k60hz_active_adapter_m-f/
A proper DisplayPort or HDMI to USB-C solution would take a USB 3.x input so that it can support not only the USB 2.0 + four lane DisplayPort option (which the LG requires), but also a USB 3.x + two lane DisplayPort option for USB-C docks or USB-C displays that don't require four lanes.
Example converters that do this are the Sunix UPD2018 (only supports HBR2 link rate though), and any Thunderbolt 3 add-in card but those have a PCIe upstream instead of a USB 3.x upstream so they are not a general solution.
bizlink.com had this vapourware solution: https://www.bizlinktech.com/products/detail/1332/VirtualLink™+Interface+Adapter
It says you are using a 5120x2880 framebuffer and outputting 3840x2160 60Hz. That's probably the best you're going to get using an HDMI to DisplayPort adapter.
But it doesn't look like you're using an HDMI adapter in this AGDCDiagnose output because I see DisplayPort DPCD registers. But the EDID seems to be greatly modified so you might be using an HDMI adapter? I am confused. How exactly is the display connected in this AGDCDiagnose output? What Computer, GPU, adapters, cables? It may be that the HDMI port is controlled by a DisplayPort to HDMI adapter. That would explain the presence of DPCD.
You only sent output for one mode so I can't compare to see what you were getting before.
Your MacBook Pro has an older AMD GPU so the AGDCDiagnose output is not clear about the pixel format. Maybe output from AllRez might give more info.
You can try using SwitchResX to create a custom timing of 4096x2304. Try this timing from the older LG UltraFine 5K (model 27MD5KA) EDID:
Code:
DTD: 4096x2304 59.999273 Hz 16:9 142.198 kHz 593.820000 MHz (aspect 16:9, no 3D stereo)
Hfront 8 Hsync 32 Hback 40 Hpol P
Vfront 1 Vsync 8 Vback 57 Vpol NLol woke up this morning and fired up the PC and both LG UltraFine displays came on and are working as expected, so no idea why that wasn't the case yesterday, cuz I didn't make any changes, but we're good to go!
I think it depends on which display it detects first. If it's the LG 5K then it will be the only display to work but it will work at 5K. If it's the 4K then both displays will work but the 5K will only be outputting 4K.
Would the expectation be that the SIIG adapter should enable 4K/60 from the PS5 to the 5K Ultrafine (27MD5KL-B)? I tried the CAC-1334, which was only able to output at 1080p. Just wanting to make sure before I order.
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Am I correct in understanding that the Wacom Link Plus cannot convert a DisplayPort or HDMI signal to an LG 5k 27MD5KA-B? I had thought that all Thunderbolt 3 connections were just running a DisplayPort signal, but it sounds like that's not the case.
Gawd I hope the Apple Studio Display can manage this somehow… I really don't have space for more than one display in my life.
Gawd I hope the Apple Studio Display can manage this somehow… I really don't have space for more than one display in my life.
It depends on the PS5 software. It might not like the EDID from that HDMI to USB-C adapter.
An alternative in that case would be this thing which lets you select between 4 EDIDs:
https://www.siig.com/hdmi-2-0-to-displayport-1-2-converter-4kx2k-60hz.html
with a bi-directional USB-C to DisplayPort cable, or the Belkin Charge and Sync Cable, or the Wacom Link Plus.
Or maybe you can fix the CAC-1334 issue using an HDMI EDID modifier thingy.
https://fsrinc.com/fsr-products/product/dr-edid-manager-learner/category_pathway-143
Is there such a device with a USB interface that lets you enter an arbitrary EDID? Maybe those kind are too expensive.
Correct. You need a Thunderbolt 3 add-in card to convert DisplayPort to Thunderbolt for the 27MD5KA. The DisplayPort signal in a Thunderbolt connection is encapsulated into Thunderbolt packets, similar to how Ethernet can do http and smb on the same connection (Thunderbolt 3 is two lanes of 20 Gbps but DisplayPort 1.2 is 4 lanes of 5.4 Gbps; a Thunderbolt lane is a pair of lines, one for receive and one for transmit; DisplayPort lanes are single direction).
The Apple Studio Display is compatible with non-Thunderbolt hosts like the LG 5k 27MD5KL is.
Thank you, Joe, that made perfect sense.
Where did you find that information on the Apple Studio Display? I dug into the tech page on Apple and it didn't say much… did you derive that from device compatibility (iPads or whatever)?
Where did you find that information on the Apple Studio Display? I dug into the tech page on Apple and it didn't say much… did you derive that from device compatibility (iPads or whatever)?
The tech specs is all the info we have for now. Plus some statements from Apple:
https://forums.macrumors.com/thread...l-work-with-pcs-but-with-some-caveats.2337225
Some of the iPads listed as compatible with the Studio Display are USB-C (non-Thunderbolt) which must use HBR2 with DSC to achieve 5K60 10bpc RGB otherwise the iPad would be limited to lower color depth or lower refresh rate or lower resolution. The tech specs have a note that this connection method limits USB speed to USB 2.0. This is expected for a non-Thunderbolt connection.
The Mac mini 2018 does not have HBR3 or DSC so it must use two HBR2 connections for 5K60 like it does for the LG UltraFine 5K.
We don't know if the Studio Display supports a single HBR3 connection mode. I don't think the XDR display does.