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

[Amethyst1]

Are there any alternatives to the Wacom connector linked above that would work?

The Wacom Link Plus will not work with the 27MD5KA.

The 27MD5KA requires Thunderbolt 3 video input so you need a Thunderbolt 3/4 add-in card with two DisplayPort inputs (e.g. the Gigabyte GC-ALPINE RIDGE or GC-TITAN RIDGE) and route two DisplayPort connections from your RTX 2070 to it, then connect the 27MD5KA to the Thunderbolt card.

That’s your only option I’m afraid. Two DisplayPort connections from the GPU are required to run the monitor at full 5K resolution (this is known as “dual-link SST”).

 

[Mcdevidr]

Studio Display got a 5k resolution with a gigabyte add in card and one display port connection, i believe the LG is different though. I dont like that you cant control brightness still however on the studio display as with the LGs you can with some 3rd party apps.

 

[Amethyst1]

Studio Display got a 5k resolution with a gigabyte add in card and one display port connection, i believe the LG is different though.

The 27MD5KA will not do 5K at all via one DisplayPort connection.
The 27MD5KL will do 5K at 39 Hz via one DisplayPort connection but that requires setting up a custom CVT-RBv2 timing.

 

[etc]

Studio Display got a 5k resolution with a gigabyte add in card and one display port connection, i believe the LG is different though. I dont like that you cant control brightness still however on the studio display as with the LGs you can with some 3rd party apps.

Try installing BootCamp. You should be able to control brightness using BootCamp control panel or keyboard shortcut.

 

[Arausio]

Good Day Experts!
I received the LG 4K Ultrafine display (model: 24MD4KL) today and tried connecting it via the bidirectional cable to my PC and could not get the display to show anything. I also connected the power cable to the monitor. The port I was using to connect on the monitor was labeled as USB-C, not the one with the Thunderbolt symbol.
Specs:
Graphics Card: Geforce GTX 1660Ti // Windows 10 x64
Cables: Version 1 Version 2
Please help me understand what am I doing wrong?

 

[joevt]

Good Day Experts!
I received the LG 4K Ultrafine display (model: 24MD4KL) today and tried connecting it via the bidirectional cable to my PC and could not get the display to show anything. I also connected the power cable to the monitor. The port I was using to connect on the monitor was labeled as USB-C, not the one with the Thunderbolt symbol.
Specs:
Graphics Card: Geforce GTX 1660Ti // Windows 10 x64
Cables: Version 1 Version 2
Please help me understand what am I doing wrong?

Use the Thunderbolt port. It will take a USB-C input. The USB-C ports of the display are only USB data (will be limited to USB 2.0 speed if connection to PC is not Thunderbolt).

 

[Arausio]

I tried connecting to all of them, USB-C, Thunderbolt on the monitor itself. I tried two different kinds of bidirectional cable too, to no avail.

 

[Arausio]

I've been beating my head agaisnt this all night. I also have a work PC laptop with Thunderbolt capability and I tried connecting it to the monitor with the Thunderbolt cable provided with the monitor, and it worked. I saw the picture on the monitor. Now, why it doesn't work with my 1660Ti graphics card and that bidirectional cable - no idea. Does anyone else have any ideas on this?

 

[Eric_WVGG]

That display works exclusively over Thunderbolt. Yes, it is possible to run a Displayport signal over Thunderbolt, but that display doesn't do it. I encountered the same issue with my LG 27". (the newer 27" do Displayport, but not the original, which I was stuck with)

This is a dead end, I'm afraid. I just gave up and got an Apple Studio display.

 

[Amethyst1]

That display works exclusively over Thunderbolt. Yes, it is possible to run a Displayport signal over Thunderbolt, but that display doesn't do it. I encountered the same issue with my LG 27". (the newer 27" do Displayport, but not the original, which I was stuck with)

This applies to the original 27”(27MD5KA), but not to the 24” (24MD4KL). The 24” even comes with both Thunderbolt 3 and USB-C cables.

 

[Arausio]

I do have a 24MD4KL model. One thing that amused me today is the fact that after 10-15 attempts of inserting the DP cable (the one that's super quality bidirectional) into either the PC end or the monitor end, actually worked! The funny part is that I disconnected everything, re-positioned the monitor to the exact position I needed for work, re-connected everything back up (DP end to the DP port on the 1660Ti and the USB-C end to the Thunderbolt port on the monitor) and, of course, re-connected the power cable, - black screen. Repeated disconnecting/re-connecting process to the 1660Ti like 10-15 times, heard the "USB device connected" sound, until after 15 attempts of said "disaster" I saw the picture displayed.
Several questions here:
1. Why doesn't the connection work the first time? It's not a user-friendly experience if each time when you need to re-position your monitor and have to spend another hour praying that your connection works after 15 attempts.
2. How to sure-proof this connection without buying an Apple laptop? Would it be meaningful to get the Wacom Link Plus for Cintiq Pro 13/16 (ACK42819) to try and see how that works?

P.S. I also found this video where it doesn't work the first time...he had to re-connect it several times
CableCreation bidirectional cable

 

[Arausio]

Guys, do you also connect/re-connect your bidirectional cable like a hundred times each time you restart your PC?

 

[Arausio]

Can anyone respond with some useful advise, I have 14 days to return this monitor and it's not looking good so far....
The Wacom Link Plus arrived today and I tried connecting it to no success. The only thing I heard was a sound but a black screen. Then, I connected another monitor via HDMI at the same time that I was testing the LG 4K Ultrafine and saw that I got an error - Display Connection Maybe Limited, each time I disconnected/re-connected power to the Wacom box. Any help at this point would be appreciated!

 

[Mcdevidr]

If you’re trying to connect from a PC gpu it aint gonna work well. Hell with the steam deck it can take several replugs and that has a USB C port. I tried to get this to work many times and its just a pain with anything but a laptop with thunderbolt or USB C (sometimes this varies). The 24 inch works perfectly fine with the surface pro 8 and 9 and also with other laptops. I had issues with the razer 14 and the monitor but it may work now with the thunderbolt 4 upgrade. The Wacom box is unreliable long term. I had one and after a couple weeks it just stopped working. If you really want this to work you’re gonna need a thunderbolt add in card or a 2080ti or another gpu with USB C (though im not sure if this passes through USB mice and stuff). Anyways good luck but sadly this is just how it is until a reliable hdmi to USB C cable comes out (i actually have one adapter, it works for about 2 min then cuts in and out). Also you can run an egpu signal through a surface pro or other laptop with igpu and two thunderbolts. You plug in egpu then the display in the other and this does work as far as performance loss im not sure but it does work.

 

[Arausio]

If you’re trying to connect from a PC gpu it aint gonna work well. Hell with the steam deck it can take several replugs and that has a USB C port. I tried to get this to work many times and its just a pain with anything but a laptop with thunderbolt or USB C (sometimes this varies). The 24 inch works perfectly fine with the surface pro 8 and 9 and also with other laptops. I had issues with the razer 14 and the monitor but it may work now with the thunderbolt 4 upgrade. The Wacom box is unreliable long term. I had one and after a couple weeks it just stopped working. If you really want this to work you’re gonna need a thunderbolt add in card or a 2080ti or another gpu with USB C (though im not sure if this passes through USB mice and stuff). Anyways good luck but sadly this is just how it is until a reliable hdmi to USB C cable comes out (i actually have one adapter, it works for about 2 min then cuts in and out). Also you can run an egpu signal through a surface pro or other laptop with igpu and two thunderbolts. You plug in egpu then the display in the other and this does work as far as performance loss im not sure but it does work.

Thanks, Mcdevidr for your honest response.
What I've noticed with my setup is that the this cable works on 2K resolution fairly seamlessly. I have also tried the Moshi cable and was surprised to find out that it works seamlessly on 4K resolution. My thinking, at least at this moment, is that the other cables/adapters are garbage quality...
I'm not sure if I'll have long-term reliability with the Moshi cable though...
Do you know anyone who's had success with these bidirectional cables, how long do they last for?

 

[Mcdevidr]

Thanks, Mcdevidr for your honest response.
What I've noticed with my setup is that the this cable works on 2K resolution fairly seamlessly. I have also tried the Moshi cable and was surprised to find out that it works seamlessly on 4K resolution. My thinking, at least at this moment, is that the other cables/adapters are garbage quality...
I'm not sure if I'll have long-term reliability with the Moshi cable though...
Do you know anyone who's had success with these bidirectional cables, how long do they last for?

Not sure about longevity but I finally got the goovis hdmi to usb c to work. What was happening is I plugged into the usb c power but for whatever reason that caused the screen to go out after a minute or two. Just using the adapter is pretty solid without the power. Also works with my switch. I’m gonna probably give away my desktop though as I just like running my macs at this point and I can use steam deck on Lg fine so that’s good for me.

 

[crowe-t]

What's the earliest Mac OC that will work with the LG UltraFine 27MD5KL-B 27"? Or does the Mac OS not make a difference?

 

[etc]

What's the earliest Mac OC that will work with the LG UltraFine 27MD5KL-B 27"? Or does the Mac OS not make a difference?

I suppose High Sierra should support it. BTW you have to have TB3 port for UltraFine.

 

[Amethyst1]

What's the earliest Mac OC that will work with the LG UltraFine 27MD5KL-B 27"? Or does the Mac OS not make a difference?

macOS Mojave 10.14.5 is the oldest version to contain an .mtdd file for the 27MD5KL. This file tells macOS how the two halves of the monitor are set up so that it can appear like one large display. I wouldn’t count on the monitor working properly with an older version of macOS.

 

[crowe-t]

macOS Mojave 10.14.5 is the oldest version to contain an .mtdd file for the 27MD5KL. This file tells macOS how the two halves of the monitor are set up so that it can appear like one large display. I wouldn’t count on the monitor working properly with an older version of macOS.

Is the Apple 27" Studio Display also made with 2 halves?

 

[joevt]

Is the Apple 27" Studio Display also made with 2 halves?

Yes, but it also supports 5K60 using a single tiled mode using DSC for GPUs that support DSC.
The dual tile mode is useful for older GPUs that only support DisplayPort 1.2 or don't support DSC (since the Studio Display doesn't support HBR3 link rate).
The dual tile mode can only be used with Thunderbolt since Thunderbolt can transmit two separate HBR2 DisplayPort signals.
Without Thunderbolt or DSC, the Studio Display would be limited to maybe 47Hz (you need to be able to create a custom timing which doesn't work on Apple Silicon Macs).

 

[Ohananhan]

A true test of 27MD5KL would be without a Thunderbolt port output since both 27MD5KA and 27MD5KL can do TB. Only 27MD5KL can work without TB.


Yes, but the HDMI input of Wacom Link Plus is limited to HDMI 1.4 bandwidth which allows 4K30 or 1440p60 and the output is probably limited to < 4096 width.
You would need a CAC-1335 or CAC-1336 for > 4096 width from HDMI (if the HDMI port allows > 4096 width) if you wanted to try 5K from HDMI.

I have a CAC-1336 and when I connect it to HDMI port of Nvidia GTX 680 Mac Edition in macOS Monterey, it detects the display and shows custom 5K modes up to 5K22. 4K30 works fine. 5K22 also works (CVT-RB but not CVT-RB2). The GTX 680 doesn't have a HDMI 2.0 port but it does support width > 5K.

The display I'm using is an Acer XV273K which can accept timings to it's DisplayPort inputs up to 4K120, 5K60, 6K50, 8K30.

The CAC-1336 doesn't allow connection using a USB-C to DisplayPort cable or a USB-C to DisplayPort adapter but can connect to a Thunderbolt 4 hub (CalDigit Element Hub with Thunderbolt 4 cable) which has the display connected to it using a USB-C to DisplayPort Adapter or a USB-C to DisplayPort cable. And the TB 4 hub can have USB 2.0 devices connected to it (but only to the USB-C ports) which will also work through the CAC-1336.

An 27MD5KL is like a Thunderbolt hub with a DisplayPort display connected to it and some USB devices (for audio, camera, USB ports,...) but I don't know if it will work connected directly to a CAC-1336 with a Thunderbolt 4 cable or a USB-C cable. If it doesn't work, then connecting the 27MD5KL to a Thunderbolt 4 hub which is connected to the CAC-1336 which is connected to the HDMI port might work (but that is some expensive adapter chaining...)

I am finally back to trying to make this connection work but without much success, so any advice is appreciated.

I bought a Wacom Link Plus adapter, and I have tried connecting to my Windows PC using this with a Displayport to Minidisplayport cable. The displayport is confirmed working (connected to my old monitor which accepts DVI, HDMI and displayport). At best, I can get an error message to pop up in Windows that the connected USB device is not recognized. There is never any image output, and the LG ultrafine monitor never turns on.

On my windows PC, when I plug in the power (USB C t USB A) cable, I get a "Billboard Device" connected, so it looks like the Wacom adapter is working but is there a way to verify this?

At this point I am tempted to just buy a laptop or mini PC that has USB C video out, and give up on trying to make this 2015 PC work...

 

[joevt]

I am finally back to trying to make this connection work but without much success, so any advice is appreciated.

I bought a Wacom Link Plus adapter, and I have tried connecting to my Windows PC using this with a Displayport to Minidisplayport cable. The displayport is confirmed working (connected to my old monitor which accepts DVI, HDMI and displayport). At best, I can get an error message to pop up in Windows that the connected USB device is not recognized. There is never any image output, and the LG ultrafine monitor never turns on.

On my windows PC, when I plug in the power (USB C t USB A) cable, I get a "Billboard Device" connected, so it looks like the Wacom adapter is working but is there a way to verify this?

At this point I am tempted to just buy a laptop or mini PC that has USB C video out, and give up on trying to make this 2015 PC work...

You have yet to prove that the display is actually a 27MD5KL instead of just a 27MD5KA. A 27MD5KA will not work with a USB-C PC so that could be a waste of money. I suppose most modern PC laptops will have Thunderbolt 4 instead of just USB-C.

You said the display works with Thunderbolt Macs using a Thunderbolt connection, but you haven't tried any non-Thunderbolt connections yet with a Mac? Try the Wacom Link Plus with a Mac? You may need a USB-C to DisplayPort connection to connect the Wacom Link Plus to a Mac.

Does the Billboard Device have any identifying information that points to the LG display? USB product and vendor ID?

Check the product ID from the EDID of the display. SwitchResX can show this in macOS. CRU can show this in Windows.
LG UltraFine 5K 27MD5KA has product ID 5b11 in the EDID.
LG UltraFine 5K 27MD5KL has product ID 5b74 in the EDID.

 

[Ohananhan]

You have yet to prove that the display is actually a 27MD5KL instead of just a 27MD5KA. A 27MD5KA will not work with a USB-C PC so that could be a waste of money. I suppose most modern PC laptops will have Thunderbolt 4 instead of just USB-C.

You said the display works with Thunderbolt Macs using a Thunderbolt connection, but you haven't tried any non-Thunderbolt connections yet with a Mac? Try the Wacom Link Plus with a Mac? You may need a USB-C to DisplayPort connection to connect the Wacom Link Plus to a Mac.

Does the Billboard Device have any identifying information that points to the LG display? USB product and vendor ID?

Check the product ID from the EDID of the display. SwitchResX can show this in macOS. CRU can show this in Windows.
LG UltraFine 5K 27MD5KA has product ID 5b11 in the EDID.
LG UltraFine 5K 27MD5KL has product ID 5b74 in the EDID.

It's been a while, but I am positive it's a 27MD5KL (it's the model number written on the box). I have the same monitor with the same box at work that shows the same model number. Just to be 120% sure, I just installed SwitchResX and the product ID is 5B74.

I can connect the LG to my MBP, MBA, and iPad Pro (M2) via USB C cable or thunderbolt cable. Not sure how I'd manage to connect it using the Wacom Link Plus? All the devices are USB C/Thunderbolt output, so my only option would be to go with the Apple adapter that goes to HDMI, and then connect HDMI to Wacom Link Plus, but all the posts at the beginning of this thread mention how HDMI doesn't work.

I suspect the Billboard Device might not be initializing properly, or may need a driver, but I will need to check again when I hook up the computer. My desk space is limited (hence the desperate desire to hook up the old PC with all my old files to the LG monitor), so there's quite a bit of inertia to trying this out, hence the 6 month delay between initial attempt and now.

 

[joevt]

I can connect the LG to my MBP, MBA, and iPad Pro (M2) via USB C cable or thunderbolt cable. Not sure how I'd manage to connect it using the Wacom Link Plus? All the devices are USB C/Thunderbolt output, so my only option would be to go with the Apple adapter that goes to HDMI, and then connect HDMI to Wacom Link Plus, but all the posts at the beginning of this thread mention how HDMI doesn't work.

I suspect the Billboard Device might not be initializing properly, or may need a driver, but I will need to check again when I hook up the computer. My desk space is limited (hence the desperate desire to hook up the old PC with all my old files to the LG monitor), so there's quite a bit of inertia to trying this out, hence the 6 month delay between initial attempt and now.

You need a USB-C to DisplayPort adapter to connect the Wacom Link Plus to the Thunderbolt port of a Mac. It's kind of redundant since the Mac is USB-C so the Wacom Link isn't required - we're just doing this to test USB-C DisplayPort Alt Mode from the Wacom Link Plus instead of from the Thunderbolt port.

The Billboard Device is only there to indicate to the user that a USB-C device that has a USB-C alt mode (such as Thunderbolt) is connected to a USB-C computer that doesn't support that alt mode. "the connected USB device is not recognized" or something. On a PC I suppose you can check Device Manager to see if a display was connected - that would indicate that the DisplayPort Alt Mode was working.