LG 5K Monitor + USB-C Gigabit Ethernet Adapter

Discussion in 'Mac Accessories' started by southerndoc, Aug 20, 2017.

  1. southerndoc macrumors 65816

    southerndoc

    Joined:
    May 15, 2006
    Location:
    USA
    #1
    I was doing some speed tests on my wife's MacBook Pro (15" 2017). With wifi (802.11ac), I get about 600-800 Mbps downstream using as of yet unreleased access point using VHT160.

    I have a Satechi USB-C Gigabit Ethernet Adapter plugged into the LG 5K monitor. It's connected via CAT6 cable directly to the master switch that's connected to the router. My iMac gets 940 Mbps downstream when hardwired, but my wife's MBP could only get about 300 Mbps downstream.

    Waiting to change out the cable (if only it could be that simple), but I'm thinking it's the adapter. Has anyone had any issues with the Satechi adapters or using any adapter connected to the LG 5K?
     
  2. Phil A. Moderator

    Phil A.

    Staff Member

    Joined:
    Apr 2, 2006
    Location:
    Shropshire, UK
    #2
    Have you tried a speed test with adapter plugged straight into the MacBook?

    The upstream ports on the LG should support USB 3 speeds but I don't have one so can't check (I do get close to the theoretical maximum on my gigabit Ethernet adapter plugged straight in to my 2016 13" rMBP)
     
  3. Brookzy macrumors 601

    Brookzy

    Joined:
    May 30, 2010
    Location:
    UK
    #3
    Confusingly written post, but if I understand the gist of it, which is that the adapter is slower via the LG 5K than when hardwired, two things:
    1. The downstream USB-C ports are considerably slower than a direct connection, despite advertising 5 Gbps speeds.
    2. There are drivers for some Ethernet adapters linked in the LG 5K issues thread which some people say increased their speeds. Though I think these are for Broadcom based adapters which I’m not sure if the Satechi is.
    It may be worth investing in the Apple/Belkin adapter which apparently works well.
     
  4. southerndoc thread starter macrumors 65816

    southerndoc

    Joined:
    May 15, 2006
    Location:
    USA
    #4
    Sorry for the confusing post. Was very sleep deprived when I wrote it.

    I tried a Belkin gigabit adapter and the same thing occurred. Going to try to switch cables to see if that helps a little later.
     
  5. PosterNutbag. macrumors newbie

    Joined:
    Mar 21, 2012
    #5
    I'm having the same issue:

    2017 15" MBP (3.1/16/1TB)
    LG 27 UF Monitor
    Belkin Ethernet/USB-C Adapter

    Plugged into the LG I get around 300mbps up/down from speedtest. When I plug directly into the mac, the speedtests are around 950mbps up/down

    I also hooked up a TB Display off my MBP and used the Ethernet port on the TB display. 950mbps up/down from that connection as well.

    Something is up.
     
  6. southerndoc thread starter macrumors 65816

    southerndoc

    Joined:
    May 15, 2006
    Location:
    USA
    #6
    Am I mistaken in thinking that the LG should handle the bandwidth?

    Who do we contact to report this as a possible bug (if it is)?
     
  7. PosterNutbag. macrumors newbie

    Joined:
    Mar 21, 2012
    #7
    If my Thunderbolt monitor that was made in 2011 can handle the bandwidth.... I'd like to think a monitor built in 2016 with a Thunderbolt 3 interface can do the same.

    It's also not limited by the bus internally if it works fine when directly attached.
     
  8. dyn macrumors 68030

    Joined:
    Aug 8, 2009
    Location:
    .nl
    #8
    How are you speed testing it (I'm hoping it is with either an internal ftp or smb filetransfer that you time or by using something like iperf; some website is not going to work at all)? Is there a difference when you connect it directly to the Mac instead of the display?
     

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