Hi Guys,
I have mostly the same concern, so here is a copy of my Chat with LG support regarding this issue.
Nevertheless, on second though, I beleive I didn't ask the right question to LG support.
I asked them if the LG 34WK95U could work the same way the Dell UP2715K did, in order to widen to bandwith to allow transfer of a 5K signal at 60hz on dual DP1.2 port.
As you will see their answer to this question is NO.
The right question should have been... Can we use the LG 34WK95U at 60hz and native resolution using the Usb C entry on the monitor and the TB2 (DP1.2) port on the Mac Pro late 2013 (thus a Usb C to TB2 apple connector)?
And I will explain after the chat retranscription why I believe this config should work..(but shoud be tested).
Firstly: Copy of the Mail + Chat with Duane from LG Support 21 08 2018.
Mail of 18 08 2018 :
Dear sir, dear madam,
The MAC PRO Late 2013 comes with 6 Thunderbolt output (= 6 miniDisplayPort 1.2), split on 3 controllers.
Each controller can support one 4K monitor at 60Hz, or even 1 5K monitor if the monitor offers 2 DP1.2 inputs.
It was the case of the Dell UP2715K.
Unfortunately Dell stopped its production and no other monitor are replacing it.
The Dell UP3218K (8k 32 inch) monitor comes with 2 Display port 1.4, but event using 2 DP1.2 from the MAC PRO, we can't get a 8K Image.
The LG34WK95U offers 5160*2160 pixel (which is less than a real 5K - 5120*2880).
This means that Using 2 DP1.2, the MAC PRO should be able to use this monitor at his full resolution.
My question to LG guys is then:
Would it work using on the Mac Pro:
- one TB output with a "Mac Adapter TB3 to TB2", connected to the Usb C port of the monitor,
- Plus one second TB output with a "miniDisplayPort to DisplayPort cable", connected to the Displatport of the monitor.
It should be tested, but it should work...
NB: For information the MAC PRO late 2013 is said to be limited to 6 WQHD (27 inch 2560 * 1440) screens.
I tested it with 6 UWQHD (34 inch 3440 * 1440) screens, which is far above Apple specs. but IT WORKS fine (at 60 Hz NTSC).
Technically, combining 2 Thunderbolt ports (full DP1.2 bandwith of 1 controller) allows to go up to real 5K.
So my question is reduced to :
"Has this screen be designed to be used with 2 cables combined to tranfer the signal, like the Dell UP2715K was ?"
If Yes, then the MAC PRO will be able to support up to 3 of these screens and LG should advertise this info to the Apple community.
A lot of users (having older hardware) are indeed frustrated not to be able to go to the 5K screens offering only UsbC Connectors.
Thanks for letting me know if someone tested this config.
Best regards
Michel
Chat of 21 08 2018 :
MICHEL : … I would like to check with your engineering department if the LG34WK95U has the same specifications as the Dell UP2715K had, allowing backward compatibility to Hardware equiped with dual DP1,2 port. And if not, I hope that your engineers will make a variant of this model that will offer this possibility.
MICHEL : I sincerely beleive that there is a market for "Backward Compatibility", especially that no other 5K or 4.5K (like yours) offers this functionality at this time.
DUANE : thanks for waiting, we are able to raise your concern and based on my info here , what you are inquiring is not possible the monitor only supports a direct 5 k signal per input and per port , connecting 2 ports into the monitor is not a capability of the unit.
DUANE : … also each port supports 5k@60hz except the HDMI, each port is directly forwarded to a direct input, it is not possible.
MICHEL : It is technically possible, just a question of electronic behind. Let your engineers see what Dell was offering in their UP2715K and you'll have the solution.
MICHEL : … as I mentionned, no one on the market is offering backward compatibility anymore (Dell did it during a few month). I'm sure there is a Market for that. And your unit already comes with 1 USBc connector + 1 DP connector, so it's just a question of electronics behind to split to signal in 2 DP1.2...
MICHEL : So please let me know if any developments.
DUANE : What you need here is to update your computer. We at LG uses the current industry standard for our monitors and it's fixed and cannot be updated due to it being a physically part or hardware wise as for your concern rather this is a hardware difference you may need to check with apple to update your computer. It's not an issue with our monitor which is fine on it;s own but rather may be a limitation with your mac causing it to be incompatible.
DUANE : Thank you for your time and patience. It has been a pleasure to assist you today. Should you have any further questions or concerns, please do not hesitate to contact us again. Thank you for choosing LG Electronics. We appreciate your business. Have a great day!
Duane has exited. This chat has been closed.
End of discussion…
Secondly:
Why do I beleive the LG 34WK95U should work at 60hz and native resolution (5160*2160) using the Usb C entry on the monitor and the TB2 (DP1.2) port on the Mac Pro late 2013 (thus a Usb C to TB2 apple connector)?
Please check the following table (source https://en.wikipedia.org/wiki/DisplayPort)
It tells you that the bandwith of DP1.2 (standard supported on TB2 from Mac Pro late 2013) is 17,28Gbit/s.
This is the maximum bandwith of each of the 3 controllers of the Mac Pro Late 2013.
Using this table plus the web site from
https://www.pxcalc.com/
and calculating additional intermediate resolutions, I come to the following table:
This shows that the LG 34WK95U should use 16,68Gbits/s bandwitdh at 60Hz and native resolution, which is just under the max. supported bandwitdth of a DP1.2 Controller, and the Mac Pro Late 2013 has 3 of them.
Please let me know if you know someone who could test this config.
Best regardsto the community
Michel
