To future proof higher-end displays: mDP or HDMI?

Discussion in 'MacBook Pro' started by rawdawg, Jul 13, 2017.

  1. rawdawg macrumors 6502

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    #1
    I recently bought the new 2017 MBP. I am looking at the OWC 10-port dock but it comes in either mDP or HDMI. I thought with the newer USB-C interface perhaps mDP is going away on newer displays.

    My current displays aren't great, but I run (2) 24" @ 1080. In the future I do plan to upgrade them.

    The mDP versions are more expensive and the HDMI are "limited stock". I don't know if this reflects the fact that one is more popular than the other.

    Any advice would be appreciated. thanks
     
  2. jerryk macrumors 68040

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    #2
    Some monitors do not have mDP, but almost all have mDP or DP. And you can get mDP to DP cables
     
  3. rawdawg thread starter macrumors 6502

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    #3
    Hi, did you mean "some monitors do not have HDMI..."? So are you saying mDP would be the better choice?
     
  4. jerryk macrumors 68040

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    #4
    No I did not say anything about HDMI. But yes, I thing DP (or mDP) is a better choice.
     
  5. rawdawg thread starter macrumors 6502

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    #5
    Yes, originally you did not say anything about HDMI. But you wrote, "Some monitors do not have mDP, but almost all have mDP or DP".

    So what I mean is, did you mean to say that? Sounds like it is a typo because it cancels itself out.

    Thanks for your reply, I do not mean to be confused.
     
  6. robvas macrumors 68030

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    #6
    mDP is dead as far as apple is concerned

    USB-C or HDMI...
     
  7. ZapNZs, Jul 13, 2017
    Last edited: Jul 13, 2017

    ZapNZs macrumors 68020

    ZapNZs

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    #7
    Being 3.1 gen 1 might be the determining factor to how future proof this dock can be? As this is a 3.1 gen 1 dock, does it support one 4k @ 60 hz or is it limited to 4k @ 30 hz? (if it can do 60, will all other devices run at USB 2.0 speeds?)

    If it does only support one 4k display at 30hz, you might find that to be OK or you might also find it to be incredibly annoying.
     
  8. killawat macrumors 65816

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    #8
    I say skip all of them. That price is way too high for simply USB-C functionality, especially with TB3 docks such as the TS3 Lite available. But this one charges, so thats kinda nice. Still, you may run into bandwidth issues.

    Also OWC says right at the bottom: *15-inch MacBook Pro 2016 is currently not compatible. This probably includes the 2017 MBP as well.
    This may mean that it just isn't working properly for some reason or It could just be that it doesn't provide enough juice to charge under high load.

    Now onto the future proofing discussion. For all intents and purposes, Displayport is the most flexible display technology on the market today. The latest versions of the available ports, HDMI 2.0 and DisplayPort 1.2 (commonly used, though DisplayPort 1.3 is the newer version) can both do 5k and all the good stuff. There are some individual protocol niceties that I won't get into. Ultimately, this dock doesn't do 5k so thats not a consideration.

    Displayport++ lets us have the best of all these things. So you can use DisplayPort, HDMI, VGA and DVI as your requirements change. The mDP port on this dock will support 4k @ 30hz , and supports Displayport++ (including HDMI)

    But like I said, I would much rather go with one of TB3 solutions
     
  9. New_Mac_Smell macrumors 68000

    New_Mac_Smell

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    #9
    If you want to future proof it make sure it has USB-C really.

    HDMI is terrible for computers and hopefully dead soon. DisplayPort is just the PC version of HDMI and is trundling along. VGA I have no idea why I still see that on some things, it's been 30 years! DVI is just an early version of DP really. Anyway, hopefully they'll all disappear from PCs and be replaced with USB-C.

    So make sure it has USB-C, or get a cheap USB-C - Whatever dongle for $10 and change that as and when needed.
     
  10. rawdawg thread starter macrumors 6502

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    #10
    Thanks for the replies. Called OWC and they said they tested this dock with the new 2017 MBP and it works, so for $109 for the HDMI version I'm giving it a test
     
  11. ZapNZs, Jul 14, 2017
    Last edited: Jul 14, 2017

    ZapNZs macrumors 68020

    ZapNZs

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    #11
    If it only supports one display, and that display maxes at 4k @ 30 hz, I don't know if it makes as much of a difference either way since 30 hz for web browsing is a bit rough... :(

    --- Post Merged, Jul 14, 2017 ---
    Why do you think OWC would do this? If this dock was 3.1 gen 2, I'd be all over it...but with multiple displays, it's not a one cable solution, and if I had two 4k displays then I would either need to plug both of them directly into the MBP (which does not work as I don't have enough ports) or plug one into this dock and get 30 Hz and plug the other into the MBP and presumably get 60 Hz if using the right USB-C-->mDP/HDMI2.0 adapter (which would annoy me insanely given the cursor seems almost choppy at 30 hz compared next to 60!)

    Why are Makers being so slow with 3.1 gen 2? 3.1 gen 2 seems like the real solution when one wants enough bandwidth for an all-in-one dock at a price less than Thunderbolt options!
     
  12. killawat macrumors 65816

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    #12
    I blame Apple. The best they could have done would have been to include Thunderbolt 3 in the 2015 MacBook. Acer and Lenovo both included TB3 in their notebooks around the same time (the first time ever that a version of Thunderbolt had not been first on a Mac), Imagine where we would be at with all these solutions. USB solutions could still exist, but Thunderbolt 3 solutions would also have had time to be tested and perfected, then ramped up for the 2016 MacBook Pro.

    I understand how tiny the logic board is in the MacBook and I'm no electrical engineer, my guess is that back in 2015, the only way to get the chips enabling USB 3.1 Gen 2 were unavailable or unreliable, and the Alpine Ridge chips probably weren't available in massive quantities. So the dock makers responded by only creating Gen 1 docks.
     
  13. burgman macrumors 68000

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    #13
    Why when plugging in the cheapest Surface Pro to a 4 K monitor with mDP one gets 3840 by 2160 @60hz? USB-C has many advantages but not for displays vs mDP. Apple uses two DP 1.2 streams for 5k and had to use USB-C to get thin. Your declaration of death isn't accurate at all.
     
  14. New_Mac_Smell macrumors 68000

    New_Mac_Smell

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    #14
    The USB-C ports on the Mac are TB3 ports though, which are equal or greater than all other media ports as it incorporates all of them. I've got a USB-C to HDMI cable right here that outputs at least 4K 60Hz.

    DisplayPort and HDMI are effectively the same thing, just as HDMI and DVI-D are effectively the same thing, audio bandwidth is the main thing with HDMI, which is why it was designed for TVs and not computers. So not quite sure what you're saying here?

    Don't all cables only support one display unless you daisy chain TB? Seems the issue is with the display you're using, a 4K 30Hz display is no good, so don't use one?
     
  15. ZapNZs, Jul 15, 2017
    Last edited: Jul 15, 2017

    ZapNZs macrumors 68020

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    #15
    I worded that poorly - bear with me as I'm not great with the exact specs and terminology and my understanding in this arena is far from perfect. I meant the dock as the primary limitation rather than the cable or monitor. The CalDigit USB-C dock supports two monitors (IIRC mirrored in OS X, and multi stream in Windows), although I am not sure about the OWC as they do not specify this very clearly. The problem with both is that the docks are USB 3.1 gen 1, capping out at 5 Gbps, placing considerable limitations on what future display can be connected to these docks with a usable refresh rate while also leaving sufficient bandwidth to use something like an external SSD, high speed SD card, and/or high speed flash drive simultaneously at reasonably good (or even marginally acceptable) transfer speeds. With the CalDigit C-dock, I believe you can use one display at 4k @ 60 hz, but the consequence is everything else connected to the dock will run at less than USB 2.0 speeds. With this OWC, it does not specify what revision the DP or HDMI is or if it can support 4k@60.

    Hypothetically, USB 3.1 gen 2 can support all the way up to something insane like 8k @ 60hz. The MBP has USB 3.1 gen 2, some SATA SSDs in RAID 0's use USB 3.1 gen 2 (like the SanDisk Extreme 900), and I imagine a SATA protocol that exceeds 6 Gbps isn't all that far away to enable higher speed external hard drives. But with the dock being only 3.1 gen 1, it really can't take advantage of any of this. Consequently, even though DP arguably has more flexibility than HDMI, I do not know if any output configuration on this dock can make it future proof as 4k increasingly becomes the standard because there just might not be enough bandwidth to make this an all-in-one solution even for a single UHD display. Consequently, I'm still looking for the one cable solution and hoping we see a Gen 2 charging dock sometime soon that is priced lower than the TS3 Lite.
     
  16. killawat, Jul 15, 2017
    Last edited: Jul 15, 2017

    killawat macrumors 65816

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    #16
    Well, almost. The bandwidth used for DisplayPort is unaffected by the bandwidth used for USB on a given USB-C port. It is possible to have a USB-C port that offers USB Gen 1, Gen 2, Power Delivery or DisplayPort individually, any combination thereof, all the above, or a superset that includes Thunderbolt 3. Just depends on what package you buy from TI or Intel. The Displayport side in a dock can be 1.1-1.4, but you'll usually see DisplayPort 1.2 because of maximum compatibility and cost.

    [​IMG]
     
  17. ZapNZs, Jul 15, 2017
    Last edited: Jul 15, 2017

    ZapNZs macrumors 68020

    ZapNZs

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    #17
    Always interesting to learn in this area as there is so much to it!

    Why does the USB speed decrease to 2.0 on the CalDigit USB-C dock if using 4k @ 60 hz over DP? Is this because all superspeed lanes are being used by the DP stream, leaving only the high speed lane left for USB data?
     
  18. killawat macrumors 65816

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    #18
    It looks like that should only be a limitation of the Macbook 2015 which makes sense. The processor/iGPU is hooked up to a DMI 2.0 running at a max of 2 GB/s which = 16 Gigabits per second.

    A Displayport 4k 30hz stream requires 6.18Gbit/s of bandwidth whereas the a 60 Hz stream requires 12.54 Gbit/s bandwidth.

    So a 4k60 stream running at 12.54 Gbit/s won't allow you to achieve the full 5 Gbit/s for a USB 3.0 connection (because 17 is greater than the total amount of bandwidth to the DMI) , hence the negotiation is at a lower speed. THats probably why they limited the 2015 MB to 4k30.

    Thats my best guess. Of course, the 2016+ MBP should never experience something like this because they're using DMI 3.0 and have more PCIE lanes to work with.
     
  19. Adamantoise macrumors 6502a

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