LG 34WK95U resolution at MacOS Catalina 3440x1440 instead of 5120x2160 via TB3

Question

Level 1

30 points

LG 34WK95U resolution at MacOS Catalina 3440x1440 instead of 5120x2160 via TB3

Strange thing happened with my external 5K2K LG 34WK95U display after upgrading today my MBP (late 2018/Vega20) from Mojave to Catalina.

When the OS started first time after upgrade I got nothing on the display at all (USB devices connected to the monitors hub continued to work fine), then after manual restart I got the picture, but lost native resolution.

The LG OSD told me that Catalina is sending via Thunderbolt 3 only 3440x1440@60 instead of 5120x2160 I had on Mojave, and in Displays control panel I lost options to use "Scaled/More space" modes, getting physical resolution settings instead, with the maximum of 3440x2160.

For sure I wasn't changing any setting on my display, and during the update it was just plugged into my MacBook like every day before.

When trying different things to discover the solution I found that when changing Display Port version from 1.4 to 1.2 in LG onscreen menu I get 5120x2160@60 and scaling in Displays control panel back. But I'm sure in Mojave the display was working with DP set to 1.4 without any problems.

Ok, I'm fine working with DP 1.2 having full resolution, but... wondering what changed and why DP 1.4 worked on Mojave and don't work on Catalina.

Any ideas what to do with this?

Posted on Oct 7, 2019 3:05 PM

Reply

Answer 1

danytone

Level 1

12 points

Nov 6, 2019 12:50 PM in response to THG.ru

Guys

since I installed Catalina and I no longer have the right version of True Color to install, so I have the same problem that I had the first few weeks when I bought the monitor. Since I have the vertical stand for my macbook (so it remains closed) I go into stand-by mode using Stop, but every time I switch it back on the monitor turns on but without DAS mode activated and no image / input comes in and goes into standby . Do you have this problem? Thanks.

Reply

Answer 2

danytone

Level 1

12 points

Dec 23, 2019 5:21 AM in response to jakobvad

I have tried several times to explain the problem to both LG and Apple but nobody listens to me. Honestly, I also got tired. However, I think the main problem is the video card at the time of wake up.

Reply

Answer 3

Jan 3, 2020 1:50 AM in response to THG.ru

Apple or LG or whoever is able to fix this issue, come on!!

I just purchased the LG 34WK95U a few weeks ago, loved it on Mojave. During the holiday break I finally upgraded to Catalina, unaware of this issue, coming back to my photo studio just realizing I can't use the monitor's full potential!

Ugh! Unfortunately DP 1.2 is not a reliable solution for me as I need the "10-bit" colors.

Am I supposed to return this monitor?

Reply