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LG UltraFine 5K on Windows PC problem

H

HelloAgain16

macrumors member
Original poster
Nov 19, 2019
42
4
Hello altogether,
so I have an LG UltraFine 5K display which I currently connect to a Windows PC with an RTX 2070 Super via USB-C. Basically this works as you would expect. Windows 10 shows up properly. But after some time after starting the System, a bug occurs. I can then see tiny white flicker in form of stripes on the right side of the screen and in the middle part, normally not on the left side. And on top of that, the display seems to start loosing the connection to the PC for a short time. This loss of connection endures for some seconds, then I can see Windows again with this flicker. While the connection is lost, the display goes completely black! In most scenarios, I can fix this problem by unplugging and then replugging the display! Has anyone of you got an idea on how to fix this problem. I changed the video driver several times while the problem keeps occurring, so I don't think it's that. And I am on the newest update of windows. When I connect a MacBook to the display with BootCamp, everything works just fine without these issues.
Thank you for your replies!
 
I’m guessing you have newer revision of the 5K.
Almost seems like there may be an issue with the display using display port over usb (c) since your thunderbolt 3 Mac works fine. First I would try replacing the cable with a high quality USB-C cable.
I assume dont have another USB-C equipped PC to test with as well? That would be helpful to diagnose. It’s generally one of three things: your PC, the cable, or the display itself.
 
So the USB-C cable comes directly out of my graphics card! The PC also has a USB-C connector but I tried connecting it to that but it doesn't output video it seems! The USB-C cable is the one that comes with the monitor which should be and feels like it is of high quality! I can try using my tablet with the USB-C cable and see if the same bug occurs, then I can say whether it is the cable or not!
 
So I tested the cable with the tablet and it works just fine as well without any problems. Could it be that Windows hasn‘t got an apropriate driver for the LG display? And if so can I maybe install the driver that I get with BootCamp as in BootCamp it works just fine and I can also control the brightness!
 
I’m thinking your running into issues because of the usage. The video card output is designed for VR and you’re trying to force DisplayPort signals.
You will save yourself a lot of headaches if you use a bidirectional DisplayPort to USB-C cable. (displayport out on gpu, USB-C on monitor). Something like this but longer obviously: https://www.startech.com/AV/display...ters/3ft-usbc-displayport-cable-4k~CDP2DP1MBD
 
This could be the issue! Thank you very much for your answers! I will try it with a displayport cable then! I hope this helps!
 
Hello together!
I have news concerning the solution with a displayport cable! I bought the moshi bidirectional cable and since I use it all the issues with flickering and loosing the connection are gone! Thank you very much for that hint! Unfortunately there are some tradeoffs that come with this solution! First, to answer your question runtime_error: you can‘t use the display in 5K! The moshi cable could do 5K60Hz but the monitor only accepts this via true thunderbolt which has a unique way of transferring the data! It is a little complicated but it only works in 4K60Hz! I have heard though that 5K30Hz might work as well but I can only go up to 4 and a bit K in Windows so I have no idea on how to do 5K! And second: since I now use the displayport of the graphics card, I loose the functionality of the USB-C connection I had previously! The microphone of the monitor doesn‘t work with the moshi cable and if you connect a peripheral to the monitor it won‘t work either! So keep this in mind when using a displayport-based cable!
I hope this helps you guys and thank you very much for your support!
 
HelloAgain16 said:
Hello together!
I have news concerning the solution with a displayport cable! I bought the moshi bidirectional cable and since I use it all the issues with flickering and loosing the connection are gone! Thank you very much for that hint! Unfortunately there are some tradeoffs that come with this solution! First, to answer your question runtime_error: you can‘t use the display in 5K! The moshi cable could do 5K60Hz but the monitor only accepts this via true thunderbolt which has a unique way of transferring the data! It is a little complicated but it only works in 4K60Hz! I have heard though that 5K30Hz might work as well but I can only go up to 4 and a bit K in Windows so I have no idea on how to do 5K! And second: since I now use the displayport of the graphics card, I loose the functionality of the USB-C connection I had previously! The microphone of the monitor doesn‘t work with the moshi cable and if you connect a peripheral to the monitor it won‘t work either! So keep this in mind when using a displayport-based cable!
I hope this helps you guys and thank you very much for your support!
Click to expand...
I purchased this cable and it is not working with my GPU. I have GTX 1080 ti dont know if that makes a difference or not. Are you using the LG app or anything to get windows to recognize the monitor?
 
Hello Gundicoulus! I am not using the LG App or anything! For me it just works! Are you using the newer or older model of the LG UltraFine? And 5K or 4K?
 
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