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

[Amethyst1]

It's a passive adapter.

Ugh. Try an active one that explicitly supports 3840×2160.

 

[Amethyst1]

Just testing out my SIIG adapter with the different devices I have around.

What devices, out of curiosity?

 

[joevt]

What devices, out of curiosity?

I think this one: https://www.siig.com/hdmi-to-usb-c-port-4k-60hz-converter-adapter.html
which is similar to https://www.club-3d.com/en/detail/2517/hdmi_to_usb_c_4k60hz_active_adapter_m-f/

If you want 5K width then I think you need to wait for a new adapter that does HDMI 2.1 to DisplayPort 1.4.
https://insights.club-3d.com/thread/hdmi-2-1-to-usb-c-displayport-1-4-alt-mode/

 

[Amethyst1]

@joevt - I was inquiring about the Macs @Riviera122 tried the adapter with - sorry for being unclear.

 

[Arlaharen]

I recently brought home an LG Ultrafine 5k (suspect it's the early version) monitor from work to replace my Apple Thunderbolt Display. I have a setup where I switch between two computers (not running at the same time):
1. MBP 2019 (macOS 11.1)
2. Mac mini 2012i (macOS 10.13)

I want to be able to switch easily between my computers without having to pull the cable from the back of the monitor.
I bought the Wacom Link Plus after reading this thread. However, when plugging in the Mac mini using the mini display port the screen is black and does not seem to accept the signal. When using a Thunderbolt 2 to 3 adapter from Apple everything works. I tried updating the monitor firmware but no change.

This is what I tried:
Mac mini > Minidisplay cable or Thunderbolt 2 cable > Wacom Link Plus > Thunderbolt 3 cable > LG Ultrafine 5k

And when I try the Apple adapter this setup works

Mac mini > Thunderbolt 2 cable > Apple adapter > LG Ultrafine 5k

I essentially just want a reversed Apple adapter (I know they work in reverse) with the connectors inverted:
Male Thunderbolt 2 to Female Thunderbolt 3.

Could this be a Thunderbolt connection issue?

 

[AppleBender]

I have a working laptop Lenovo T490s I want to connect to an Ultrafine 5K model 27MBD5KA, what solution would work for this? the less cables the better.

 

[AppleBender]

Guys, success, 5K@30Hz is possible on Thinkpad T480s!

Lenovo Thunderbolt 3 Dock that I've mentioned before is not needed. It works with the display directly connected to laptop's Thunderbolt port.

Yes, I got 5K on that bloody Thinkpad with crappy Intel integrated graphics!

A bit of blind luck I guess. I've looked into needed bandwidth calculation and figured 5K@30Hz should work on that 20Gbps port. I've tried first with CVT-RB and it worked but something was slightly off. My scaled resolution (set at 200%) scaling was being reported as 2560x1441 and I've seen some slight artefacts in fonts.

So I've tried to simply replicate the same set up as for 4096 x 2304 (back porch, front porch, sync width) but with 5120 x 2880 and 29.999Hz. Amazingly enough, it works and looks super crisp.
And 30hz is good enough for job I'm doing on that laptop

I'm attaching the screenshot of joy


EDIT: I've managed to get up to 39Hz, anything above that is simply not recognized.

So what kind of cable did you use? I'm using a ThinkPad T490s as working computer and want to connect it to my 27" LG27MD5KA. I see they use the same graphics card so if you get it to work I thought it's possible on mine as well.

 

[Amethyst1]

bought the Wacom Link Plus after reading this thread.

If it is the early UltraFine, it only works via Thunderbolt, making the Wacom Link Plus useless.

 

[Arlaharen]

If it is the early UltraFine, it only works via Thunderbolt, making the Wacom Link Plus useless.

Darn it!

 

[joevt]

Darn it!

Old 5K: https://www.lg.com/us/monitors/lg-27MD5KA-B-5k-uhd-led-monitor
New 5K: https://www.lg.com/us/monitors/lg-27md5kl-b-5k-uhd-led-monitor

For the Old 5K, you need a Thunderbolt connection. Using a Thunderbolt 3 add-in card such as the GC-ALPINE RIDGE, GC-TITAN RIDGE, or ThunderboltEX 4 might work.

For the New 5K, a USB-C connection can work up to 5K 39 Hz - pixel clock ≈600 MHz. A Thunderbolt connection is required for 5K 60Hz.

 

[Amethyst1]

For the New 5K, a USB-C connection can work up to 5K 39 Hz - pixel clock ≈600 MHz.

I wonder if the display supports the tighter CVT-RBv2 timings SwitchResX can generate for a slightly higher refresh rate. (With that being said, the UF's 3840x2160 60 Hz timing uses a pixel clock of 522 MHz iirc while CVT-RB uses 533 MHz.)

 

[AppleBender]

I have a working laptop Lenovo T490s I want to connect to an Ultrafine 5K model 27MBD5KA, what solution would work for this? the less cables the better.

I'm replying here to myself to give the answer if anybody else wants to know.

My T490s had a thunderbolt port, and it works straight of the port with the oldest 5k model 27MBD5KA. No 5k resolution but I can choose from 4096x2304 60hz and 3840x2160 60hz which is good enough for what I'll use it for. Even speakers and webcam is working.

 

[joevt]

I wonder if the display supports the tighter CVT-RBv2 timings SwitchResX can generate for a slightly higher refresh rate. (With that being said, the UF's 3840x2160 60 Hz timing uses a pixel clock of 522 MHz iirc while CVT-RB uses 533 MHz.)

I read mention of a CVT-RBv3 today (in the edid-decode code). I guess you can try different vertical and horizontal blanking numbers anyway.

My T490s had a thunderbolt port, and it works straight of the port with the oldest 5k model 27MBD5KA. No 5k resolution but I can choose from 4096x2304 60hz and 3840x2160 60hz which is good enough for what I'll use it for. Even speakers and webcam is working.

I guess the T490 only has one DisplayPort connection to the Thunderbolt controller (like many pre-Thunderbolt 4 PC laptops and desktops). I wonder if the 27MBD5KA can accept a 5K 39Hz single DisplayPort timing (over Thunderbolt) like the 27MBD5KL can?

 

[Amethyst1]

I read mention of a CVT-RBv3 today (in the edid-decode code). I guess you can try different vertical and horizontal blanking numbers anyway.

Since I'll be running my 21.5" UltraFine off a Nvidia Kepler card with a 540 MHz pixel clock limit, I'll play around with timings anyway to see how high a refresh rate I can get. 48 Hz isn't bad but the higher the better.

 

[joevt]

Since I'll be running my 21.5" UltraFine off a Nvidia Kepler card with a 540 MHz pixel clock limit, I'll play around with timings anyway to see how high a refresh rate I can get. 48 Hz isn't bad but the higher the better.

Kepler supports DisplayPort 1.2 (HBR2) so it should be able to do 10bpc up to 576MHz and 8bpc up to 720MHz (minus some overhead). The new LG 5K is limited to ≈600 MHz (tested by someone else). Given that DisplayPort and the LG are digital, 600MHz doesn't really make sense. An HBR2 signal is always 5.4Gbps (per lane) regardless of pixel clock (DisplayPort uses filler bytes if the bandwidth is greater than required for the pixel clock). Is there a converter that takes DisplayPort and converts it to clocked pixels (no filler bytes, like DVI/HDMI)? In that case there may be limits for pixel clock, horizontal and vertical sync front porch, pulse width, and back porch. Maybe higher pixel clock is possible with greater horizontal and vertical sync/blanking numbers (front, pulse, back)? In that case you have to weigh the gain in pixel clock with the loss to blanking periods. The time for each part of the blanking is pixel_count ÷ pixel_clock. So once you find a limit using CVT-RB, see if you can increase the pixel clock further by increasing the sync/blanking numbers (front, pulse, back) such that new_pixel_count ÷ new_pixel_clock == old_pixel_count ÷ old_pixel_clock. Once you find a pixel clock limit, then you can try decreasing the sync/blanking numbers (front, pulse, back).

 

[Amethyst1]

Kepler supports DisplayPort 1.2 (HBR2) so it should be able to do 10bpc up to 576MHz and 8bpc up to 720MHz (minus some overhead).

I was going by this:

https://www.reddit.com/r/nvidia/comments/94e4hk

 

[Riviera122]

What devices, out of curiosity?

Post #241 contains some initial tests.

I also have tested the adapter with:

2009 MacBook running macOS High Sierra - 720p only
HP G62 laptop running Windows 7 - 480p

Have yet to experiment much with SwitchResX.

 

[Amethyst1]

11" 2013 MacBook Air, via third party Thunderbolt to HDMI adapter - Could only get 720p unfortunately. It doesn't work with a Thunderbolt 2 cable either. This could be because it's running Mavericks, so the monitor is technically not supported software-wise.

I'd suspect that Thunderbolt-to-HDMI thingy first. I've had no show-stopping issues using my 21.5" on Mavericks on a Late 2013 15" rMBP with Intel Iris Pro graphics (only 3840×2160 60 Hz) or from a Nvidia Kepler eGPU (4096×2304 48 Hz) so it being unsupported doesn't mean it won't work. This was via DisplayPort, "of course".

 

[joevt]

I was going by this:

Oh right. I tested this in Mojave with an EVGA Nvidia GTX 680 Mac Edition in a MacPro3,1 (since DisplayPort doesn't work in Catalina). It wouldn't let me do more than 539.00MHz for DisplayPort (using SwitchResX). I didn't try creating a pixel clock patch.

 

[Amethyst1]

It wouldn't let me do more than 539.00MHz for DisplayPort

The GK110 apparently can do 592 MHz which is so "frustratingly" close to the 21.5"'s 60 Hz timing (593.8 MHz).

 

[hezzak]

Hi all, I've been reading through this thread and reading up online about connecting my new Microsoft Surface Pro 7 to my LG Ultrafine 5k monitor. I find myself still a bit confused about what's possible.

My normal work machine is a 2018 Macbook Pro. However, for various reasons I need to switch over from time to time to use this new Windows machine. And I'd just like to be able to unplug the Macbook when needed, and swap in the Surface. I'm less worried about getting an amazing resolution out of the Surface.

My Windows machine:
Microsoft Surface Pro 7, i7 16GB memory 256GB SSD (product page)

My LG Ultrafine monitor:
LG Ultrafine 5k, model: 27MD5KA-B
(I bought this monitor in October 2020, but despite that, I'm led to believe that this is the older LG Ultrafine 5k model.)


I'm aware that even if I manage to get this all to work together, that I'm limited to 4k resolution at 60Hz. I don't mind that. I just want a larger monitor for ergonomical reasons, and all I have is this LG Ultrafine 5k. So I'm just searching for a way to just get video onto the monitor. (I don't care about sound, webcam, microphone, etc.)

If I indeed have the older LG Ultrafine 5k model, then that would mean that the only option for video/audio in to the monitor must be via Thunderbolt 3.

Meanwhile, video out of the Microsoft Surface is over USB-C.

I'm happy to buy a Surface Dock 2 or whatever other active adapter I might need to get video into the Ultrafine 5k. And as far as I can tell, if I grab one of these docks (or other kind of active adapter), I can get HDMI out of the dock, and I can get an adapter to go HDMI -> Thunderbolt 3 on Amazon.

But before I go grab random adapters, I was just wondering... Is this insane? Or is there some more straightforward way to just get the video, even at reduced resolution, onto the LG Ultrafine 5k?

 

[Amethyst1]

I can get an adapter to go HDMI -> Thunderbolt 3 on Amazon

These don't exist, sadly. If anything, they are Thunderbolt -> HDMI or HDMI -> USB-C, neither of which will be useful in your case - since you do have the older UltraFine 5K which requires video to be input via Thunderbolt 3.

#310

 

[ybu]

Hi,
I'm trying to connect a 24" Ultrafine with a Yoga L380 (detailled specs), Speakers only are detected with USB-C. Should I consider USB-C ->DP then DP-USB-C ? this doesn't seems logical, but I can't understand what's happening. This L380 already worked with a 22" Ultrafine...

 

[Amethyst1]

Speakers only are detected with USB-C.

That means the screen is black? Are you using the USB-C cable that came with the monitor, not the Thunderbolt cable?

 

[ybu]

That means the screen is black? Are you using the USB-C cable that came with the monitor, not the Thunderbolt cable?

Exactly, screen is black and not detected by Windows, speakers work fine. I’m using the usb-c cable. I tried this cable with my M1 MacBook Pro and it’s OK (like the TB cable).