MacOS 10.15 Catalina and LG 34WK95U-W not working at 5K

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Level 1

11 points

MacOS 10.15 Catalina and LG 34WK95U-W not working at 5K

I've seen other people complaining (on LGs forums) about compatibility issues between the 2017 MacBook Pro Radeon 560 and the LG 34WK95U-W 5K monitor, being unable to output 5K (5120x2160) natively. We were told by LG support that the issue would be '..fixed with the next version of macOS..'. Well Catalina was released today and I excitedly updated to discover.... it's still not working. Is there anything else I should try? It's very frustrating to not be able to get the best experience out of this hardware combo, after purchasing these pairing specifically.

I've tried a completely clean install of 10.15 this morning and a PRAM reset - both to no effect. As you can see from the system report output below, the highest recognized resolution of this display is 3440x1440. The issue is the same with the laptop display closed or open. If I set the display to split screen (this monitor has a screen split function to display two separate inputs side by side - either 50/50 or appox. 80/20 split), the display works at 3840x2160 and is significantly crisper. I’m using the ThunderBolt cable that shipped with this monitor. Appreciate any advice!

Model Name: MacBook Pro

Model Identifier: MacBookPro14,3

Processor Name: Quad-Core Intel Core i7

Processor Speed: 2.9 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 8 MB

Hyper-Threading Technology: Enabled

Memory: 16 GB

Boot ROM Version: 202.0.0.0.0

SMC Version (system): 2.45f1

Chipset Model: Intel HD Graphics 630

Type: GPU

Bus: Built-In

VRAM (Dynamic, Max): 1536 MB

Vendor: Intel

Device ID: 0x591b

Revision ID: 0x0004

Automatic Graphics Switching: Supported

gMux Version: 4.0.29 [3.2.8]

Metal: Supported, feature set macOS GPUFamily2 v1

Chipset Model: Radeon Pro 560

Type: GPU

Bus: PCIe

PCIe Lane Width: x8

VRAM (Total): 4 GB

Vendor: AMD (0x1002)

Device ID: 0x67ef

Revision ID: 0x00c0

ROM Revision: 113-C980AJ-927

VBIOS Version: 113-C9801AU-A02

EFI Driver Version: 01.A0.927

Automatic Graphics Switching: Supported

gMux Version: 4.0.29 [3.2.8]

Metal: Supported, feature set macOS GPUFamily2 v1

Displays:

LG HDR 5K:

Resolution: 3440 x 1440 (UWQHD - Ultra-Wide Quad HD)

UI Looks like: 3440 x 1440 @ 60 Hz

Framebuffer Depth: 30-Bit Color (ARGB2101010)

Main Display: Yes

Mirror: Off

Online: Yes

Rotation: Supported

Automatically Adjust Brightness: No

Connection Type: DisplayPort

Posted on Oct 8, 2019 9:10 AM

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Answer 1

Dec 29, 2019 5:18 AM in response to oldsnake23

i have a MBP 13" 2017. Apple website tells that my MBP can run @5120x2880 resolution. I've purchased LG 34WK95U-W monitor (with @5120x2160 resolution) but I can only use 3440x1440 resolution.

I use the TB3 -> TB3 cable that was in the box of the monitor. when I try to update monitor firmware it tells me that is already updated. my OS is Catalina 10.15.2.

I also have a flickering problem, when I plug in my Mac the Mac screen start becoming black/with/or I see the desktop; after 1 minute of flickering it works.

recap:

I can't use maximum resolution
my MBP when plugged in has a flickering problem.

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Answer 2

Dec 29, 2019 5:30 AM in response to mb2868

i have a MBP 13" 2017. Apple website tells that my MBP can run @5120x2880 resolution. I've purchased LG 34WK95U-W monitor (with @5120x2160 resolution) but I can only use 3440x1440 resolution.

I use the TB3 -> TB3 cable that was in the box of the monitor. when I try to update monitor firmware it tells me that is already updated. my OS is Catalina 10.15.2.

I also have a flickering problem, when I plug in my Mac the Mac screen start becoming black/with/or I see the desktop; after 1 minute of flickering it works.

recap:

I can't use maximum resolution
my MBP when plugged in has a flickering problem.

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Answer 3

Oct 10, 2019 11:30 AM in response to joejoo

I just got off the phone with LG support and they didn’t have an answer to give me. I installed the new firmware for the monitor and still nothing. This is a stupid problem considering the 13" macbook pros work fine, but all of us that spent more on our computers are left with nothing. Can someone please resolve this once and for all.

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Answer 4

mb2868 Author

Level 1

11 points

Oct 10, 2019 11:47 AM in response to joejoo

Joejoo - are you using a USB-C cable or a Thunderbolt 3 cable? They look exactly the same / have the same connectors, but the bandwidth requirements for 5K are more than a plain USB-C cable (like the charging cable that comes with your MBP) can handle. I've tested with both the cable that came with the monitor and a brand new Apple Thunderbolt 3 cable that I purchased specifically to test with - I still have the problem I described above, but at least I get 60Hz.. Still not full performance of the monitors we purchased, but better..?

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Answer 5

Oct 10, 2019 11:50 AM in response to mb2868

There was no way I could find it in the Monitor itself, The Lg Rep just told me there was a new firmware as of Oct 1 2019. But I don’t think it was an actual firmware update, just software for your Mac, not the monitor itself. here a link to the support page https://www.lg.com/ca_en/support/support-product/lg-34WK95U-W

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Answer 6

mb2868 Author

Level 1

11 points

Oct 10, 2019 11:54 AM in response to ColbyKlash

Thanks - did you manage to install it under Catalina? I just tried and I got a message from MacOS saying the package can't be opened because Apple cannot check it for malicious software. Oh the irony..

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Answer 7

mb2868 Author

Level 1

11 points

Oct 10, 2019 11:57 AM in response to mb2868

This note seems to imply (a) that it would be fixed by Catalina (it wasn't) and / or that it's supported using a Thunderbolt 3 > DisplayPort cable - anyone give that a try? https://www.lg.com/uk/monitors/lg-34WK95U

Something like this? https://www.amazon.com/Infinnet-DisplayPort-Bidirectional-Thunderbolt-Certified-1-5/dp/B07R3ZQBS6/ref=sr_1_4?keywords=thunderbolt+3+displayport+5k&qid=1570733808&sr=8-4#customerReviews

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Answer 8

mb2868 Author

Level 1

11 points

Oct 10, 2019 12:14 PM in response to ColbyKlash

Thanks ColbyKlash - that let me install the OSD software. When I asked it to run the monitor software update, it told me I was already running the latest version (3.02, 2.14). I've ordered a USB-C > DisplayPort (Thunderbolt 3 / DP 1.4) cable today - will report back when I test it tomorrow, hopeful based on your comments this is a solution for me (that otherwise involves me replacing the laptop or monitor, to get access to full resolution).

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Answer 9

Oct 19, 2019 1:50 PM in response to mb2868

Hey all. I'm on Catalina 10.15 w/ the latest Supplement Pack and I'm also using an LG 34WK95U-W. I think I've found a solution to help OS X see the monitor at the right resolution.

In the monitor's OSD setting, change the DisplayPort version to 1.2 (back from the default v1.4). Also, I use the back left Thunderbolt connector (back left when the laptop screen its open - that is, the furthest Thunderbolt port on the left). The only let down is that using DisplayPort v1.2 doesn't enable HDR, but hopefully it will work soon with a future Catlina release. I hope this helps.

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Answer 10

mb2868 Author

Level 1

11 points

Oct 19, 2019 2:47 PM in response to xingyein77

Very odd - I tried this, it didn't help, the max I still see is 3840x2160 (or 3440 x 1440 to use full widescreen). I tried all 4x Thunderbolt ports on my MBP and 2 different USB-C TB3 cables. I also tried it before and after applying the Catalina supplement pack. Sigh...

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Answer 11

GaliocL

Level 1

12 points

Oct 27, 2019 9:37 PM in response to xingyein77

Hi Xingyein77 ,

Which type c to Displayport cable was used from you ?

I try to using the type c to DisplayPort made by "Moshi" then still not working w/ 5k resolution.

Check below link :

https://www.amazon.com/Moshi-USB-C-DisplayPort-Support-Thunderbolt/dp/B077S9DZGK/ref=cm_cr_arp_d_product_top?ie=UTF8

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Answer 12

GaliocL

Level 1

12 points

Oct 28, 2019 10:28 AM in response to mb2868

Hi mb2868 ,

I'm using the 10.15 that can working fine .. umm , but I using the MacBook Pro 13" 2018 with Touch Bar.

I have another problem with the "Moshi 5K usb c to displayPort" that can not achieve @5k resolution.

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Answer 13

mb2868 Author

Level 1

11 points

Oct 28, 2019 4:26 PM in response to GaliocL

I'm using 10.15 right now - updating to Catalina didn't help. One of the early Beta versions of Catalina did work - but it was reverted back / broken in a subsequent release and not solved in the final release (for me).

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Answer 14

Oct 29, 2019 6:45 PM in response to mb2868

My LG 34WK95U-W was working perfectly in Catalina until I updated today to the Catalina 10.15.1 update. I had the monitor in DP1.4 mode, and I was using a USB-C to Displayport cable.

Now I can only get 2560x1080 HiDPI at 30Hz, and the Refresh Rate dropdown in display settings is grayed out. I've tried changing to DP 1.2, and tried resetting SMC and PRAM. Nothing helps.

What's most annoying is that there was a while, a few months after this monitor was released, that the Thunderbolt 3 cable was working perfectly. Somehow Apple broke that a few months later, and I've been forced to use a DP cable. And now, even DP isn't working except at 60Hz.

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Answer 15

Oct 31, 2019 8:06 AM in response to oldsnake23

Btw in my last message, I meant to say "...and now, even DP isn't working except at 30Hz. "

SwitchResX can only solve this issue if you're willing to disable System Integrity Protection, which is a really bad idea.

I'd urge everyone with this issue to call both Apple Support and LG Support to report this issue, so that they have enough confidence that this is a widespread issue and therefore worth spending time to solve (and not just a random defective hardware issue with a tiny number of people).

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MacOS 10.15 Catalina and LG 34WK95U-W not working at 5K

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