DisplayPort to Thunderbolt 3, MacBook Pro 2018 Vega


#1

Hello :wave:

I’m own the recent Samsung LC49RG90SSUXEN, an ultra wide monitor, 49" for a resolution of 5160x1440p @ 144Hz

It works just fine on Windows with a display port câble, connected to a GTX 1070.

But I’m also the owner of an Apple MacBook Pro 2018 with the Vega 20.
When I connect an HDMI cable to my adapter ( this one https://www.amazon.fr/gp/product/B07DLLV911/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1 ), the resolution is 3840x1080 @ 60Hz.
I’ve look around the web and your products seem really great, I can feel you know what you are talking about :smiley: .
Which one of your product is adapted to my situation ?

Thanks a lot, it is really great to see companies who care.


#2

Hi,

Thanks for reaching out to us, I am happy to help answer your question, although I don’t think we have a USB-C graphics adapter that will be fully compatible with this display.

Our USB-C to DisplayPort 1.2 cable ( https://plugable.com/products/usbc-dp ) has been tested with 4K UHD ( 3840x2160 ) displays at 8-bits per color channel with modern MacBook systems and may be our most compatible adapter, however it may not work fully with this display. This display at 5120x1440 with 10-bits per color channel actually requires more bandwidth than either the cable or the MacBook is capable of producing to drive the display at full resolution, refresh rate, and color depth.

Additionally, the MacBook’s Thunderbolt 3 port supports DisplayPort 1.2, while this monitor is designed for DisplayPort 1.4 connectivity. The USB-C to DisplayPort cable can be used to connect this display I cannot guarantee the results will be optimal. For example the refresh rate may be limited to 30Hz, which may provide enough bandwidth to drive the display, however the overall resolution may also be reduced as you are seeing with your current adapter.

The results should be better than the current adapter but may not be optimal. USB-C adapters provide two sets of conductors capable of supporting DisplayPort or USB 3.1 Gen 2 communications. In the case of a multiple function adapter like the one linked above, one lane is used for DisplayPort while the second is used for the USB devices. This limits the 4K output to 30Hz refresh rate and is likely also limiting the resolution of this display. Our USB-C to DisplayPort cable can provide both lanes for DisplayPort signal and can provide for 4K output at 60Hz refresh rate. Depending on how well this display handles scaling and how the MacBook handles the very large resolution this may allow for better support for this display but it will not be 100% compatible.

Based on Samsung’s product page ( I could only find the page in German ) it looks like this display offers a side-by-side picture mode that could be used for a seamless dual screen setup using two graphics adapters ( the current multi-function adapter and a separate USB-C graphics adapter ). Using two connections may be a functional alternative to a single connection with the MacBook pro. I recommend consulting the user manual that came with your display to make sure it supports this feature and what inputs are supported. This may not work if the system identifies both connections as the same display, I cannot be 100% sure as the documentation I can find is in German and I do not trust the translations I have on hand.

I am sorry we do not have a single adapter solution that will work with this display, however it looks like it may be possible to use this display with two connections to the computer in extended desktop mode as a “single extended display”.

Please let me know if this helps, or if you have any additional questions.

Pat
Plugable Technology
support@plugable.com


#3

Thank you very much for this very detailed explanation.

After reading you message I was surprise that the latest Macbook Pro 2018 do not support DisplayPort 1.4. I checked online and found sources that state the opposite ( ie : https://www.idownloadblog.com/2018/07/20/2018-macbook-pro-displayport-1-4/).

Your trick about the SideBySide is clever :slight_smile: I’ll try with my windows desktop to see if it detects two monitors or one.

Having 60hz at full scale would be nice to start with :slight_smile:
I think for my use case it may do the trick :

  • I use HDR for photos only, so not big bandwidth
  • Full refresh rate is mostly for gaming on my windows desktop, even if it’s always nice to have smoothness even for work, it’s not a sea breaker.
  • Full resolution all the time

I’ll try your cable :wink:

Edit : if I understand correctly the limitation comes from the non-support of DisplayPort 1.4 right? If it supports 1.4 do you have another solution than the cable?

Thank you very much, I’ll come back with feedbacks!


#4

Hi,

Thanks for the link, that is interesting as it was my understanding that the new Titan Ridge chipset was installed but the HBR3 ( High Bit Rate 3 ) and DSC ( Display Stream Compression ) had not been enabled at a software level. So this is great news!

We do not currently sell a USB-C to DisplayPort 1.4 adapter or cable.

For HDR, MacOS will prioritize 10-bits per color channel ( HDR10 ) over refresh rate, even if the system is not currently displaying HDR content, this will most likely cause reduced refresh rate at higher resolutions, however if used with two adapters in extended desktop mode this will most likely not be an issue.

Pat
Plugable Technology
support@plugable.com


#5

I come back with feedbacks :

I purchased your cable, DisplayPort 1.2 to USB-C and I also purchased a DisplayPort 1.4 cable with a DP 1.4 to USB-C adapter (from the same company, to be sure).

On my screen, I see no difference between the two cables, the screen information show me the same resolution and the same refresh rate, and I ran several tests, no difference : 5160x1440 @ 120 hz.

Also, surprisingly, MacOS displays HDR content correctly, but Windows 10 does not ! I installed the Samsung drivers from their website but it simply doesn’t.
Also Windows 10 advanced details from my screen shows “Fake 8 bits” …


#6

Hi,

I am glad the USB-C to DisplayPort cable is working with your system! This cable passes the USB-C DisplayPort Lanes directly to the output and while not specifically designed or tested to meet the DisplayPort 1.4 specifications it is great to know it is working!

I am not sure about the Windows 10 message, is it possible to attach a screenshot of the message that shows the “Fake 8 bits”?

Thank you!

Pat
Plugable Technology
support@plugable.com


#7

Hi,

I made a basic translation from french, I switched my Windows to english and it says “8-bit with dithering”.

I realized some of my tests were flawed because I use Firefox on Windows, which doesn’t support all HDR content type.


#8

Hi,

Thanks for the clarification! That makes a lot of sense.

Windows provides instructions for enabling HDR content here ( https://support.microsoft.com/en-us/help/4040263/windows-10-hdr-advanced-color-settings ). Engadget has a rundown of setting up HDR in Windows here ( https://www.engadget.com/2019/01/27/hdr-setup-explainer/ ). It seems that even for the writer of the article it took some effort to get everything working at HDR10.

I hope this is helpful, please let me know if you have any additional questions.

Pat
Plugable Technology
support@plugable.com


#9

Hello,

We’re closing this thread due to inactivity, but if you have any further questions please feel free to contact support@plugable.com and we’ll be happy to help.

Thanks,

Pat
Plugable Technologies
support@plugable.com


closed #10