LG 34WK95U (UltraWide 5k monitor) and MacBook Pro 2018

I think all of those Thunderbolt 3 to Dual DisplayPort adapters (there's more than 20 of them) only support 5K on displays like the Dell UP2715K that use two DisplayPort 1.2 connections (they use the older Alpine Ridge Thunderbolt controller). Any dock that says they support 5K and uses Alpine Ridge Thunderbolt controller can connect a 5K display that requires two DisplayPort 1.2 connections either over a single Thunderbolt 3 connection or with two DisplayPort cables.

Moshi has a USB-C to DisplayPort cable supporting 5K (supports DisplayPort 1.4) and is bidirectional (so it could be used as a DisplayPort to USB-C cable).

https://www.apple.com/ca/shop/product/HLR62ZM/A/moshi-usb-c-to-displayport-cable

If you have a computer with Thunderbolt 3 ports that support DisplayPort 1.4 then there's a Thunderbolt 3 to Dual DisplayPort 1.4 adapter that may work (it uses the new Titan Ridge Thunderbolt controller).

https://www.globalsources.com/gsol/I/DisplayPort-adapter/p/sm/1163916845.htm#116 3916845

I wonder why the notice on the LG UK site is not on the US site?

I wonder why the Notice says the USB-C port is limited to only 4K (non-Thunderbolt) but the manual says the max resolution for USB-C is 5K 60Hz. This is where I would try the Moshi bidirectional cable - connect the USB-C end to the display.

Well I did test this one and it worked perfectly.

https://www.amazon.com/dp/B075B1GQFP/ref=ox_ya_os_product

Its description states:

"... Plugable Thunderbolt 3 to Dual DisplayPort Display Adapter Compatible with Late 2016/2017/2018 MacBook Pro Systems (Supports Up to Two 4K 60Hz Monitors Or One 5K) ..."

I got the full 5120 x 2160 Resolution. I used the Display Port cable that came with the monitor.

Nonetheless, the quick fix of...

- Restarting the computer with the monitor directly connected to the Thunderbolt-3 port

- Disconnecting the cable from the monitor after the keyboard lights go out

- Plugging the cable back in after the Apple logo appears

Works for me as well. No attachments, no extra power cable.

There have been reports that the current 10.14.2 beta works as well. I like the monitor so much now, I'm considering buying a 2nd.

I just got the same monitor. It works fine on my 2016 MacBook Pro and my 2017 MacBook Pro, but not, as you indicate, on my 2018 MacBook Pro. Your results on your 2018 MacBook Pro are better than mine. Mine just keeps flipping around and can never make a connection. It just goes to show you. You should dig deep before spending $1500, and then dig deeper. Nonetheless I am quite happy with the monitor and look forward to all the bugs being shaken out so that I can use it with my primary machine.

LG Themselves acknowledges the problem at LG 34” 21:9 UltraWide™ WUHD (5120 x 2160) Nano IPS Display | LG UK

I'm going to attach their supported connection chart which shows the various ways of connecting the monitor. Of particular interest you might want to look at the USB-C to DisplayPort Connection which supposedly works on the MacBook Pro 2018 providing full 5120x2160 @60Hz. As I read the chart it indicates that the that the connection to the monitor is the DisplayPort end (obviously as the MacBook Pro only has USB-C/ThunderBolt 3).

So the question is which USB-C DisplayPort adapter do you use. You have to be careful here because most indicate they only support 4K @60Hz max, no matter what the MacBook Pro can handle.

I looked around and I found this: https://www.amazon.com/dp/B075B1GQFP/ref=ox_ya_os_product

Its description states:

"... Plugable Thunderbolt 3 to Dual DisplayPort Display Adapter Compatible with Late 2016/2017/2018 MacBook Pro Systems (Supports Up to Two 4K 60Hz Monitors Or One 5K) ..."

The encouraging part being the "Or One 5K."

There are several adapters that offer the single 5K btw.

https://www.amazon.com/Nekteck-Certified-Thunderbolt-DisplayPort-Converter/dp/B0 6XYL72RL/ref=sr_1_2?s=electronics&ie=UTF…

https://www.amazon.com/Wavlink-Thunderbolt-DisplayPort-Adapter-Converter/dp/B07C LLX6XS/ref=sr_1_7?s=electronics&ie=UTF8&…

https://www.amazon.com/SIIG-Thunderbolt-Dual-DisplayPort-Adapter/dp/B07611SJW1/r ef=sr_1_15?s=electronics&ie=UTF8&qid=1541944261&sr=1-15&keywords=usb-c+to+displa yport+5k%4060hz

https://www.amazon.com/Sonnet-Thunderbolt-Dual-DisplayPort-Adapter/dp/B073H78ZZP /ref=pd_sbs_147_2?_encoding=UTF8&pd_rd_i…

There are also docks that provide this feature.

In the box that came with your monitor you should have received a DisplayPort <--> DisplayPort cable. So I'm going to try connecting the Thunderbolt end to my MacBook Pro to the DisplayPort of the monitor and if it works I will report back here, and on Reddit where I also saw your post.

The nice thing is that if this works, it means I can connect my 2017 and 2018 MacBook Pros to the monitor simultaneously and access them just by switching inputs on the monitor. Theoretically. Bad news is that this little puppy is $75. So you might want to wait until you find out what happens to me before dropping your $75.

LG Statement:

Good Luck!!

I have to go collude with a Russian.

2016 MacbookPro 15

Until the Mojave update just a few minutes ago, it was the latest Sierra with all security updates. At the beginning of this saga tonite, I hadn't done that latest security update, did that somewhere in my troubleshooting, made no difference.

Processor: 2.9 GHz Intel Core i7

Memory: 16 GB 2133 MHz LPDDR3

Graphics: Radeon Pro 460 4096 MB, Intel HD Graphics 530 1536 MB (both)

Drivers: I did no manual driver updates

Cables: ultimately just the LG supplied TB cable worked for both power and video, after Mojave update

Extras: I did need to use SwitchResX to actually select the 5120x2160, but it was just a click, didn't have to do any crazy recovery boot/terminal work.

Also, for what it's worth for those still struggling, if this hadn't worked, my next step was going to be a solution I just read was working for many others: Connect a separate power cable to the MBP (the factory charging brick/cable) in addition to the TB cable going to the monitor, and make sure the TB is in the front right port for some reason. Worth a shot if you haven't tried it.

I suspect there's some validity to it, since the message I got on the dark monitor when attempting to swap the TB cable for a USB-C was that I "need 2 USB-C cables". I think it was trying to say you need power separately. Even before trying the USB-C, I noted the resolution is was giving me with the TB was as if it wasn't recognizing it as a TB cable.

I don't think that adapter supports 5K over a single DisplayPort connector. Realize that frame buffer size does not always equal output resolution. It's possible that the output resolution in your case is 4K. The 5K frame buffer is scaled down to fit the output resolution. Another possibility is that the output resolution is 5K 30Hz instead of 5K 60Hz.

Some displays will show the output resolution and refresh rate. This is usually the case with my Dell displays except for HDMI resolutions where for 4K it says 2160p without the refresh rate so I can't tell if it's doing 30Hz or 60Hz.

The best way to see the output resolution is to double-click the current resolution in SwitchResX and note the active vertical and horizontal pixels, and the vertical scan rate. Also, note the pixel clock - it should be approximately 966 MHz for 5K (16:9), approximately 703 MHz for 5K2K (21:9), 533 MHz for 4K (DisplayPort), and 594 MHz for 4K (HDMI 2.0).

Like many home-made you tube videos, that one is also tremendous waste of pixels. Most of its information could have been condensed into a brief written article with no loss of significance, and far easier reference to pertinent facts.

Two possible take-aways that were mumbled in passing:

"Requires Discrete GPU: not supported on the [implied 13-in model] with only Integrated Graphics."

"the 2018 MacBook Pro and Mojave currently have a problem that keeps this display from working properly"

Make certain you have the latest version of Mojave (10.14.1 at this writing) and the Security Update that was issued about 6 November 2108.

Beyond that, you may need to contact the manufacturer for more support.

Yes, I am having exactly the same issues. The full 5k works sometimes after a reboot with switching to different USB-C ports back and forth (praying and swearing) for me.

It's looks like it's a known issue related to the latest MacBooks 15" in which either LG or Apple or both have to fix.

According to LG:

"...this compatibility issue is not being caused by the monitor and so is something that you would have to contact Apple about in order to receive further information. I am sorry for any inconvenience that this may cause..."

The interesting thing is that they also recommended a cable to me that says it only supports 4K @60HZ. I might try one of the cheaper cables at some point just to see if it works.

So I guess I will go report the monitor problem as a bug to Apple to see if there is any acknowledgement or the typical silence of the Gods.

------ Full LG response ------

Hi Marvin

Thank you for your response.

I have received a response back from my technical team and they have advised me that this compatibility issue is not being caused by the monitor and so is something that you would have to contact Apple about in order to receive further information. I am sorry for any inconvenience that this may cause.

In regards to your query relating to the USB-C to DisplayPort cable, this is not something that LG manufacture, however I have included a link below that will confirm the price and availability of this product.

https://www.amazon.co.uk/DisplayPort-uni-Thunderbolt-MacBook-Pixelbook/dp/B075V2 7G2R/ref=sr_1_6?s=electronics&ie=UTF8&qid=1542039399&sr=1-6&keywords=usb+c+to+d i splayport

Should you have any questions regarding LG products in the future, please do not hesitate to contact us again for assistance.

If you have any questions or queries please either call us on 0344 847*** or use our live web chat option on our website www.lg.com/uk

Kind Regards

Ryan

LG Electronics UK Help desk

One more interesting update: I've booted up into my Bootcamp with Windows 10 on the same Macbook and the display works properly over the Thunderbold 3. This probably proves that the problem is not on the hardware side and more of a macOS issue.

The 15-in 2018 MacBook pro supports up to two at 5220 by 2880

USB Type-C™ is a specific feature of a product, it is not a generic description. Think of “USB Type-C” as an adjective, not as a noun.

from:

http://www.usb.org/developers/usbtypec/USB_Type-C_Language_Product_and_Packaging _Guidelines_FINAL.pdf

EXACTLY what cables/adapters are you attempting to use?

You are absolutely 100% correct and I should have stipulated that this is at 30Hz. For my purposes which are largely typing and working on remote desktops, servers, routers, switches and code, virtual Windoze, virtual LINUX, this is fine. If I were looking for higher refresh rate I probably would have gone with a different adapter. It was an experiment for me. I installed SwitchResX to confirm as you advised:

The monitor is indeed running at 30Hz but comfortably with the resolution I wanted.

I did find, a day or so later, an adapter for the same cost that notes 5K at 60Hz:

Ableconn TBT3-DPX2 [Certified] Thunderbolt 3 to Dual DisplayPort Adapter for Mac and Windows Systems - Support Two UHD 4K 60Hz or single 5K 60Hz https://amzn.to/2Q28UQA

Still, at this point I'm happy with the standard Thunderbolt-3 cable connection:

I did also, but they finally got around to responding to me this morning. They asked for the sysdiagnose and I just supplied it. I'm also receiving the Thunderbolt to DisplayPort cable today and look forward to trying that.

I recently purchased this monitor as well to use with my 2018 15" MacBook PRO with Vega20 Graphics. I too am having connectivity issues and here is primarily what's going on. When I plug the display in, 80% of the time it'll work without any issues, until MacBook goes to sleep. Once it goes to sleep, I cannot wake it up no matter what I do. Even if I disconnect the external display, I cannot wake the MacBook. It gets super HOT near the Power button and at the edge where the screen is attached. The only way to remedy the issue is to hold down the Power Button and reboot! Also, there's no Monitor Brightness Controls or Volume Controls if you are using the Monitor Speakers available via your external keyboard. Lastly, the Auto Brightness on the monitor seems to occasionally fluctuate even though the ambient lighting has no change.

Pretty darn disappointing given the price tag of this Monitor. I expect these types of bugs to be caught during the New Product Introduction stage of the Verification Process before the product is released to High Volume Production! Shame on LG and APPLE for giving us substandard products that don't play well together. Hopefully they're working on the fixes!!