LG 5K Monitor + USB-C Gigabit Ethernet Adapter

southerndoc

macrumors 65816
Original poster
May 15, 2006
1,092
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USA
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?
 

Phil A.

Moderator
Staff member
Apr 2, 2006
5,513
2,319
Shropshire, UK
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)
 
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Brookzy

macrumors 601
May 30, 2010
4,778
4,813
UK
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.
 
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southerndoc

macrumors 65816
Original poster
May 15, 2006
1,092
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USA
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.
 
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PosterNutbag.

macrumors newbie
Mar 21, 2012
20
0
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.
 
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southerndoc

macrumors 65816
Original poster
May 15, 2006
1,092
67
USA
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.
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)?
 
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PosterNutbag.

macrumors newbie
Mar 21, 2012
20
0
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.
 
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dyn

macrumors 68030
Aug 8, 2009
2,708
384
.nl
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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_wli

macrumors newbie
Mar 7, 2018
15
1
I just ran into this issue and after going through all possible bottleneck (there were a few switches and routers around home), also came into this simple problem.

The LG Ultrafine 5K's USB-C port in the back somehow limited my network speed to around
300mbps down / 600mbps up

when plugged various ethernet dongles directly to my macbook pro, I get around
900mbps down / 900mbps up.


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)?
[doublepost=1535724342][/doublepost]https://forums.appleinsider.com/dis...ith-thunderbolt-3-for-apples-2016-macbook-pro

It seems the USB-C port speed of this monitor is indeed capped.

At ~300mbps, I wonder why they still say it is USB 3.1 at 5Gbps speed.
 
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_wli

macrumors newbie
Mar 7, 2018
15
1
I have filed a bug report to Apple (https://bugreport.apple.com/web/?problemID=45730707)

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?
 
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jdmagoo1

macrumors regular
May 5, 2010
180
78
Problem solved. It has to do with the Realtek network driver that came with MacOS.
With the default driver, the speed of the network is capped at around 300mbps when it is used via the USB-C port on the LG monitor.
Once the updated driver (http://www.realtek.com.tw/Downloads...=56&Level=5&Conn=4&DownTypeID=3&GetDown=false) is installed, I can get over 900mbps on my network adapters even when it is tunnelled through the monitor.
Unfortunately that link doesn't work, but I found another, and now Im getting the full speed of the port as well. In fact for some reason my ethernet speed tests are quicker now than directly plugging my Satechi Hub directly into the TB3 port on the side of the MacBook

https://www.realtek.com/en/directly-download?downloadid=423db7b1ebd0abccd84fc2645de6a35f
 
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_wli

macrumors newbie
Mar 7, 2018
15
1
Unfortunately that link doesn't work, but I found another, and now Im getting the full speed of the port as well. In fact for some reason my ethernet speed tests are quicker now than directly plugging my Satechi Hub directly into the TB3 port on the side of the MacBook

https://www.realtek.com/en/directly-download?downloadid=423db7b1ebd0abccd84fc2645de6a35f
Yeah, Realtek recently updated their website and their old links no longer works.
PS: If you have an AppleTV / Homepod, can you try to
1. unplug the adapter from computer
2. wait 5 seconds
3. plug it in again
4. start itunes and select to airplay to AppleTV / Homepod

on my computers with the custom driver installed, the network would freeze and will only work after a restart.
 
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jdmagoo1

macrumors regular
May 5, 2010
180
78
Yeah, Realtek recently updated their website and their old links no longer works.
PS: If you have an AppleTV / Homepod, can you try to
1. unplug the adapter from computer
2. wait 5 seconds
3. plug it in again
4. start itunes and select to airplay to AppleTV / Homepod

on my computers with the custom driver installed, the network would freeze and will only work after a restart.
Just tested this and mine does the same, in fact it freezes my entire MacBook and have to do a hard reset. Also, after posting the above I noticed the network will freeze / drop out randomly not just with airplay. I thought maybe it was my hub, which network adapter / hub are you using?

Its a shame because Im getting the full bandwidth of the port with this driver.
 
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_wli

macrumors newbie
Mar 7, 2018
15
1
I tried TP-Link UE300 and Belkin USB-C Gigabit Ethernet.
All Realtek powered adapters are doing this.

Just tested this and mine does the same, in fact it freezes my entire MacBook and have to do a hard reset. Also, after posting the above I noticed the network will freeze / drop out randomly not just with airplay. I thought maybe it was my hub, which network adapter / hub are you using?

Its a shame because Im getting the full bandwidth of the port with this driver.
 
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omunoz470

macrumors newbie
Sep 29, 2018
3
1
Unfortunately that link doesn't work, but I found another, and now Im getting the full speed of the port as well. In fact for some reason my ethernet speed tests are quicker now than directly plugging my Satechi Hub directly into the TB3 port on the side of the MacBook

https://www.realtek.com/en/directly-download?downloadid=423db7b1ebd0abccd84fc2645de6a35f
Does anyone happen to have any alternative links for the drivers? I keep trying that link and putting my email, but it just says "Send email fail."
 
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jeme

macrumors 6502
Jun 12, 2009
266
38
Does anybody know where to get these drivers - I have a LG Ultrafine 5K and an experiencing the same thing. Internet hooked up to MacBook - 950mbps, using the Belkin adapter - 300mbps. Thanks in advance
 
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_wli

macrumors newbie
Mar 7, 2018
15
1
Does anybody know where to get these drivers - I have a LG Ultrafine 5K and an experiencing the same thing. Internet hooked up to MacBook - 950mbps, using the Belkin adapter - 300mbps. Thanks in advance
This link still works for me: https://www.realtek.com/en/componen...0-100-1000m-gigabit-ethernet-usb-3-0-software

Be warned though, this driver will give you 1GB speed but it will stall and crash your computer network when you disconnect / reconnect the network adapter (via the LG 5K monitor cable). You will need to restart your computer to get the network back.
[doublepost=1556149850][/doublepost]The driver link is https://www.realtek.com/en/componen...0-100-1000m-gigabit-ethernet-usb-3-0-software

* With this driver, you get 1GB speed but your computer needs to be restarted (network will die and all apps requiring a network will stall) if you unplug and replug your monitor / ethernet adapter.
 
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jeme

macrumors 6502
Jun 12, 2009
266
38
_wli - Thanks so much. So weird that it works great with a MBP @ 1GB and is so slow through the USB hub. Is there another USB c ethernet adapter that would work, perhaps one you are aware of? Thanks for that warning. Not sure I want to do that.
[doublepost=1556153980][/doublepost]So that link says to enter your email address to send the link and I do that but the link never arrives, checked junk mail etc. Ugh
[doublepost=1556154933][/doublepost]Finally found it here on a Targus Site, nervous about installing this.

https://www.targus.com/au/au-downloads-realtek-ethernet-driver-macos
 
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_wli

macrumors newbie
Mar 7, 2018
15
1
@jeme I gave up already and plug the gigabit directly into my MacBook Pro's 3 other free USB-C ports lol.

I think the driver from Targus site is the same as the one I got from Realtek. Can you see if it crashes your network / apps when the adapter is unplugged and replugged back into your computer (via the 5K monitor)?
 
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jeme

macrumors 6502
Jun 12, 2009
266
38
I have not installed it yet but when comparing the file it is exactly the same. Trying to decide if I am keeping the expensive monitor!
 
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_wli

macrumors newbie
Mar 7, 2018
15
1
@jeme it's a pretty good monitor; only have a minor problem with gigabyte ethernet... lol, make use of an additional USB C port on your MBP won't kill you
 
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jeme

macrumors 6502
Jun 12, 2009
266
38
Thanks _wli. If you shut down each time before reconnecting would you still have that issue? Gosh we can’t be the only folks using a harder wired connection with this monitor?
 
Comment

_wli

macrumors newbie
Mar 7, 2018
15
1
Thanks _wli. If you shut down each time before reconnecting would you still have that issue? Gosh we can’t be the only folks using a harder wired connection with this monitor?
No problem if you shutdown each time you reconnect.

Wouldn’t using the other USB C ports be easier? lol. We have like 4 of those on MBP!
 
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jeme

macrumors 6502
Jun 12, 2009
266
38
No problem if you shutdown each time you reconnect.

Wouldn’t using the other USB C ports be easier? lol. We have like 4 of those on MBP!
Lol yes much easier. I read that some folks have no issues with the driver? So for some it causes issues for others it does not.
 
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