LG UltraFine 4K and 5K: Yes you can connect it to Windows computers via DP!!!

Juno_Aug · Nov 24, 2020

Hey guys, I recently purchased the 24” ultrafine 4K 24MD4KL-B and am trying to connect it with my windows desktop (DP and HDMI available). After diving through the above discussion, I was wondering if there are two solutions to my problem:

1. Buy a DP to miniDP cable (or the reverse since DP <--> miniDP cable are always bi-directional).
Connect DP on windows to miniDP port on Wacom Link Plus, using the above cable.
Connect USB-C port on Wacom Link Plus to 24UltraFine thunderbolt port, using the cable that came with Wacom Link Plus.

2. Just buy a DP to USB-C cable (not the reverse), connect it to 24UltraFine thunderbolt port and that's it.

nwngeek212 · Nov 24, 2020

I have the new 24" 4K Ultrafine and pairing it with a Gigabyte Titan Ridge AIC. I’ve gotten the display to work by routing a DP to mDP cable from my graphics card into the TB3 AIC, but I can’t seem to get any daisy-chained USB device functionality. I have a USB 2.0 hub with a keyboard, mouse, and audio hooked up to the monitor, which are not recognized by Windows.

Any advice?

PCuser214 · Nov 25, 2020

yonile said:
@PCuser214, This is exactly the kind of solution I was looking for!
Did it work you well with PS4 connected?

Unfortunately, I have the first 5k generation screen (27MD5KA) which supports only thunderbolt, which means that I have to connect a USB-C to Thunderbolt adapter. Is it an issue?

@joevt, as the mastermind of this thread, what do you think?

PS4 and Ps5 work perfect on my LG 5K but I don't konw about Thunderbolt sorry.

Riviera122 · Nov 26, 2020

I have the 24" 4K monitor and a Mac Mini 2014. So would going MiniDisplayPort > DisplayPort adapter, to Moshi DisplayPort to Thunderbolt 3 cable work?

joevt · Nov 26, 2020

Riviera122 said:
I have the 24" 4K monitor and a Mac Mini 2014. So would going MiniDisplayPort > DisplayPort adapter, to Moshi DisplayPort to Thunderbolt 3 cable work?

Maybe, but it won't support the USB features of the display. The Moshi cable is DisplayPort to USB-C (not Thunderbolt 3).

Since the Mac mini 2014 supports Thunderbolt and the 24 inch LG UltraFine 4K display supports Thunderbolt, you should use the Apple Thunderbolt 3 to Thunderbolt 2 adapter with a Thunderbolt 2 cable. This combination will also allow you to use the USB ports of the LG UltraFine 4K at 5 Gbps (other solutions that include USB will only allow USB 2.0 from the ports).

The Mac mini 2014 is limited to 4K 30Hz.

yonile · Nov 27, 2020

joevt said:
There is no USB-C to Thunderbolt adapter. There are only the Thunderbolt 3 add-in cards for PCs. Maybe it could work if it was installed in a PC - connect a HDMI 2.0 to DisplayPort adapter to the PS4, connect the other end to the DisplayPort in of the Thunderbolt 3 add-in card. Then connect the LG UltraFine 5K (27MD5KA) to the Thunderbolt port of the Thunderbolt 3 add-in card. The Thunderbolt 3 add-in card (usually a GC-TITAN RIDGE or GC-ALPINE RIDGE) can be externally powered using certain PCIe risers in some cases (without a PC) and work with normal USB-C displays but Thunderbolt displays may be more problematic.

Bummer!
For a minute there I though that my quest has come to end

So If i understand correctly, the wacom ACK42819 would help either since it's connecting to the monitor only with usb-c cable?

(The Thunderbolt 3 add-in cards for PC solution isn't feasible for me)

joevt · Nov 27, 2020

yonile said:
So If i understand correctly, the wacom ACK42819 would help either since it's connecting to the monitor only with usb-c cable?

Correct.

jahlinux · Dec 16, 2020

Lots of information to sort through on this thread. Trying to confirm a Bi-Directional DisplayPort to USB C Cable will work with the LG UltraFine 4K Display Apple currently sells. I found this one on Amazon: CableCreation 8K Bi-Directional DisplayPort to USB C Cable

I really regret buying this display from Apple. It was over priced and now is a pain to use with anything but an Apple computer. I just purchased two 27" LG 27UN850 UltraFine displays and I'm very happy with them.

PCuser214 · Dec 16, 2020

yonile said:
@PCuser214, This is exactly the kind of solution I was looking for!
Did it work you well with PS4 connected?

Unfortunately, I have the first 5k generation screen (27MD5KA) which supports only thunderbolt, which means that I have to connect a USB-C to Thunderbolt adapter. Is it an issue?

Does your Thunderbolt support Alt-DP mode if yes the cable will work.

chrisma · Dec 26, 2020

Hi, I'm working from home currently and using a 24" LG Ultrafine 24MD4KL with a 2019 15" MacBook Pro via a TB3 cable and its perfect for most of my needs.

Unfortunately rendering times using Cycles in Blender are not great and I'd really like to try to improve this.

I first looked into mac-based options, but as OpenCL is no longer supported in OSX and Metal isn't by Blender it seems like the best solution is to build a PC with an RTX 30 series graphics card for rendering.

To complicate things I'd still like to use the Ultrafine display to work with (and switch between) both computers. If its realistic to do so...

So far this thread has been the most useful resource I've found and has led me to the conclusion that building a PC which supports Thunderbolt 3 and using that would probably give me the best chance.

But I still have lots of questions and I'd really appreciate any advice on

firstly, whether it seems like a sensible approach?
which components, like motherboards or cards that are a good TB3 choice to connect to the display?
could I switch between computers without disconnecting/reconnecting the TB3 cables?
would it be possible to still daisy chain another 4K Ultrafine display at some point in the future (even if only worked for the mac)?

Thanks!

zranger102797 · Dec 26, 2020

jahlinux said:
Lots of information to sort through on this thread. Trying to confirm a Bi-Directional DisplayPort to USB C Cable will work with the LG UltraFine 4K Display Apple currently sells. I found this one on Amazon: CableCreation 8K Bi-Directional DisplayPort to USB C Cable

I really regret buying this display from Apple. It was over priced and now is a pain to use with anything but an Apple computer. I just purchased two 27" LG 27UN850 UltraFine displays and I'm very happy with them.

Have they played nice with the M1? I’ve been considering this one heavily, along with the UL500, but leaning toward this one as it is newer and has more bells and whistles.

x2max · Dec 27, 2020

Does anybody tried the following adapter from club 3d:

Club 3D | HDMI to USB C 4K60Hz Active Adapter M/F

The Club 3D CAC-1332 is an HDMI™ to USB C Active adapter which allows you to transmit an HDMI™ Signal into a USB C DisplayPort supported Display.This product supports resolutions of up to 4096x2160@60Hz. This adapter is Uni-Directional it only works from an HDMI™ Source device to an USB C...

www.club-3d.com

It is cheaper and a little bit more handy than the Wacom solution (if it's work and HDMI output is preferred).

jahlinux · Dec 27, 2020

zranger102797 said:
Have they played nice with the M1? I’ve been considering this one heavily, along with the UL500, but leaning toward this one as it is newer and has more bells and whistles.

Yes, I’m very happy with the 27" LG 27UN850 displays

joevt · Dec 27, 2020

x2max said:
Does anybody tried the following adapter from club 3d:

Club 3D | HDMI to USB C 4K60Hz Active Adapter M/F

The Club 3D CAC-1332 is an HDMI™ to USB C Active adapter which allows you to transmit an HDMI™ Signal into a USB C DisplayPort supported Display.This product supports resolutions of up to 4096x2160@60Hz. This adapter is Uni-Directional it only works from an HDMI™ Source device to an USB C...

www.club-3d.com

It is cheaper and a little bit more handy than the Wacom solution (if it's work and HDMI output is preferred).

I've never seen that one before. It supports HDMI 2.0 (doesn't say HDMI 2.0b for HDR but that's probably because it's limited to DisplayPort 1.2a). It uses USB for power but doesn't say if it supports USB 2.0 data.

The Wacom Link Plus only supports HDMI 1.4 but it also supports USB 2.0 data.

If the CAC-1332 doesn't support USB 2.0 data, then the cable from e-Bay is probably better #159
Or use the CAC-1331 with a bi-directional DisplayPort to USB-C cable.

Update: the CAC-1332 does support USB 2.0

x2max · Dec 28, 2020

So that means if USB data is not supported than is Audio not working?

joevt · Dec 28, 2020

x2max said:
So that means if USB data is not supported than is Audio not working?

Yes, If the display uses USB audio (like the LG UltraFine 4K).
Other displays can use audio over DisplayPort or HDMI.

oreodunko · Dec 30, 2020

Hi guys, i have a question regarding a setup with the LG Ultrafine 4k 23.7".
Will a setup like this work?
Windows PC - miniDP and USB A ➡️ Wacom Link Plus - USB C to 1 of the Thunderbolt port ➡️ LG Ultrafine 4k - using a USB C from 1 of the Thunderbolt port ➡️ A Wacom Drawing Display Tablet(Wacom Cintiq Pro)

So from what i have read in this thread, everything will work from my Window PC to the LG Display. I am just wondering if it be able to relay Display/Data/ from my Wacom Drawing Tablet back to my window PC ?

Some specs requirements for my Drawing Tablet,
Graphics Input: USB-C (DisplayPort Alt Mode), or Mini DisplayPort (for up to 3840 x 2160 resolution)
PC And Mac Connection: USB-C port supporting DisplayPort Alternate Mode (for up to 3840x2160 resolution)
Power Consumption: Max. Power Consumption: 33 W, 3 W or less when asleep 0.5W or less in sleep mode (USB non-connected) or OFF mode

Thank you very much.

joevt · Dec 31, 2020

oreodunko said:
Hi guys, i have a question regarding a setup with the LG Ultrafine 4k 23.7".
Will a setup like this work?
Windows PC - miniDP and USB A ➡️ Wacom Link Plus - USB C to 1 of the Thunderbolt port ➡️ LG Ultrafine 4k - using a USB C from 1 of the Thunderbolt port ➡️ A Wacom Drawing Display Tablet(Wacom Cintiq Pro)

So from what i have read in this thread, everything will work from my Window PC to the LG Display. I am just wondering if it be able to relay Display/Data/ from my Wacom Drawing Tablet back to my window PC ?

Some specs requirements for my Drawing Tablet,
Graphics Input: USB-C (DisplayPort Alt Mode), or Mini DisplayPort (for up to 3840 x 2160 resolution)
PC And Mac Connection: USB-C port supporting DisplayPort Alternate Mode (for up to 3840x2160 resolution)
Power Consumption: Max. Power Consumption: 33 W, 3 W or less when asleep 0.5W or less in sleep mode (USB non-connected) or OFF mode

Thank you very much.

When connecting via USB-C from Windows PC, only one display can be supported, so the Wacom Drawing Display Tablet will not show a display. You need to connect the tablet to another USB-C from the Windows PC.

Or you need a Windows PC with Thunderbolt 3 (with two DisplayPort inputs from a GPU - many PCs only have one) or Thunderbolt 4 or a Thunderbolt 3 add-in card with two DisplayPort inputs.

If your Windows PC is running Windows, then you could possible power two 4K 60Hz displays from a single DisplayPort port using a DisplayPort 1.4 MST Hub that supports DSC. You would need a GPU that supports DSC, otherwise you would be limited to 4K 60Hz 8bpc. You would still want a method to convert the two DisplayPort outputs to USB-C for the display and tablet.

cataclysmicvoid · Jan 8, 2021

joevt said:
I've never seen that one before. It supports HDMI 2.0 (doesn't say HDMI 2.0b for HDR but that's probably because it's limited to DisplayPort 1.2a). It uses USB for power but doesn't say if it supports USB 2.0 data.

The Wacom Link Plus only supports HDMI 1.4 but it also supports USB 2.0 data.

If the CAC-1332 doesn't support USB 2.0 data, then the cable from e-Bay is probably better #159
Or use the CAC-1331 with a bi-directional DisplayPort to USB-C cable.

You've collected some very useful info in this thread @joevt, thank you.

You suggest using the CAC-1331, do you believe it supports USB audio or you are saying the 1331 + a DP to USB-C cable would be equivalent to the CAC-1332? (I have an email out to Club 3D to inquire if either supports USB data — I doubt it.)

So, to review what's been collected in the thread, if you want 4K/60Hz HDMI / DP output into LG Ultrafine with USB-C alt mode input plus audio / webcam support:
- Wacom Link Plus (via DP input) + HDMI-to-DP adapter (e.g. CAC-1331)
- Belkin Charge and Sync Cable for Huawei VR Glass + HDMI-to-DP adapter (e.g. CAC-1331)
- unbranded eBay cable (#159)

without audio / webcam support, more options, including:
- Club 3D CAC-1332
- Club 3D CAC-1331 + bi-directional DP - USB-C cable (e.g. AmazonBasics)
- others?

Limited to 1080p or 4K@30Hz:
- CAC-2330 + bi-directional DP - USB-C cable
- Foinnex HDMI-DP Cable (#156) + bi-directional DP - USB-C cable
- Wacom Link Plus (via HDMI input), but many issues reported? (supports USB audio)

And out of curiosity... if you want 5K it's Thunderbolt 3 or bust?

joevt · Jan 8, 2021

cataclysmicvoid said:
You've collected some very useful info in this thread @joevt, thank you.

You suggest using the CAC-1331, do you believe it supports USB audio or you are saying the 1331 + a DP to USB-C cable would be equivalent to the CAC-1332? (I have an email out to Club 3D to inquire if either supports USB data — I doubt it.)

So, to review what's been collected in the thread, if you want 4K/60Hz HDMI / DP output into LG Ultrafine with USB-C alt mode input plus audio / webcam support:
- Wacom Link Plus (via DP input) + HDMI-to-DP adapter (e.g. CAC-1331)
- Belkin Charge and Sync Cable for Huawei VR Glass + HDMI-to-DP adapter (e.g. CAC-1331)
- unbranded eBay cable (#159)

without audio / webcam support, more options, including:
- Club 3D CAC-1332
- Club 3D CAC-1331 + bi-directional DP - USB-C cable (e.g. AmazonBasics)
- others?

Limited to 1080p or 4K@30Hz:
- CAC-2330 + bi-directional DP - USB-C cable
- Foinnex HDMI-DP Cable (#156) + bi-directional DP - USB-C cable
- Wacom Link Plus (via HDMI input), but many issues reported? (supports USB audio)

And out of curiosity... if you want 5K it's Thunderbolt 3 or bust?

The LG UltraFine 4K only support audio through USB.

A DP to USB-C cable cannot transmit USB.
The CAC-1331 cannot transmit USB.
The CAC-1332 could transmit USB but it is not mentioned as a feature, so it probably does not transmit USB. I hope they answer your e-mail about this question.

Your summary of the options is correct. There may be other options but they probably have the same limits/capabilities.

For 5K, Thunderbolt 3 is required for the LG UltraFine 5K. The Dell UP2715K and HP Z27q requires two DisplayPort 1.2 inputs like the LG UltraFine 5K, but does not require those inputs to come through Thunderbolt.

If you have DisplayPort 1.4 then a single connection can give 5K 60Hz 8bpc on a display like the Iiyama ProLite XB2779QQS. I don't know of any HDMI to DisplayPort adapters that will do 5K. Certainly there are modes that allow 5K from HDMI - 938 MHz pixel clock can be output from HDMI 2.0 using 10bpc 4:2:0 but DisplayPort 1.2 doesn't support 4:2:0, there are no adapters that output DisplayPort 1.4, and I don't know if the display itself supports 4:2:0. The adapters themselves may have a width limit of 4096 pixels, so cannot do 5K even if the refresh rate is reduced to 30Hz.

I remember someone got 5K working using DisplayPort 1.2 6bpc RGB on the XDR (from Windows Nvidia GPU where you can change the bpc setting). The XDR does not support chroma sub sampling. HDMI 2.0 has lower bandwidth than DisplayPort 1.2, so 5K 60Hz 6bpc requires at least 4:2:2 but the display might not support chroma sub sampling and while DisplayPort 1.2 can do 4:2:2, I chroma sub sampling requires 8bpc or greater.

Update: the CAC-1332 does support USB-C with USB 2.0 + DisplayPort 1.2

cataclysmicvoid · Jan 9, 2021

joevt said:
The LG UltraFine 4K only support audio through USB.

Thank you Joe.

To confirm, the 5K UltraFine also only supports audio over USB?

joevt said:
If you have DisplayPort 1.4 then a single connection can give 5K 60Hz 8bpc on a display like the Iiyama ProLite XB2779QQS. I don't know of any HDMI to DisplayPort adapters that will do 5K. Certainly there are modes that allow 5K from HDMI - 938 MHz pixel clock can be output from HDMI 2.0 using 10bpc 4:2:0 but DisplayPort 1.2 doesn't support 4:2:0, there are no adapters that output DisplayPort 1.4, and I don't know if the display itself supports 4:2:0. The adapters themselves may have a width limit of 4096 pixels, so cannot do 5K even if the refresh rate is reduced to 30Hz.

I remember someone got 5K working using DisplayPort 1.2 6bpc RGB on the XDR (from Windows Nvidia GPU where you can change the bpc setting). The XDR does not support chroma sub sampling. HDMI 2.0 has lower bandwidth than DisplayPort 1.2, so 5K 60Hz 6bpc requires at least 4:2:2 but the display might not support chroma sub sampling and while DisplayPort 1.2 can do 4:2:2, I chroma sub sampling requires 8bpc or greater.

Do these image quality concerns you mention — e.g. 10 bit color — also apply the options I listed above for HDMI/DP 4K@60Hz? If so, how? I see the 1332 says it supports 10-bit.

I assume options that work for bringing HDMI/DP 4K@60Hz to the UltraFine 4K will also work on the UltraFine 5K (as long as you have the B model using USB-C input).

I’ll report back if I hear from Club 3D.

joevt · Jan 9, 2021

cataclysmicvoid said:
To confirm, the 5K UltraFine also only supports audio over USB?

Yes.

cataclysmicvoid said:
Do these image quality concerns you mention — e.g. 10 bit color — also apply the options I listed above for HDMI/DP 4K@60Hz? If so, how? I see the 1332 says it supports 10-bit.

DisplayPort 1.2 has enough bandwidth for 4K 60Hz 10bpc RGB or 4:4:4. HDMI 2.0 only has enough bandwidth for 8bpc. You need to add 4:2:2 chroma sub sampling to get 10bpc.

cataclysmicvoid said:
I assume options that work for bringing HDMI/DP 4K@60Hz to the UltraFine 4K will also work on the UltraFine 5K (as long as you have the B model using USB-C input).

Yes. For up to 4K output. The LG UltraFine 5K does not have a 5K single connection mode, unlike the LG 5K2K or Apple Pro Display XDR.

eksu · Jan 9, 2021

Hi, I have a LG Ultrafine 5K working with a GC-Titan-Ridge, but the USB hub on the device doesn’t work.

I would like to be able to plug in a keyboard and mouse to the display then use it sort of as a KVM switching from my Mac Mini to my PC.

What drivers do I need to get USB working in windows? Does it work on Linux?

Mcdevidr · Jan 9, 2021

Anybody got audio to work on the LG4k Ultrafine with the Wacom adapter? The brightness control and audio work but the audio cracks.

joevt · Jan 9, 2021

Mcdevidr said:
Anybody got audio to work on the LG4k Ultrafine with the Wacom adapter? The brightness control and audio work but the audio cracks.

Not the first time someone has mentioned crackling audio. There's video of the problem too: