[jmerrilljr]

Can you try a different swtich, maybe a Gig-ethernet capable switch? From your log, and your LE8.2.5 iperf results, you're connecting at 100Mbp/s. I wonder if you still have problems with 4.19 when using a different switch? 

That is a gig-ethernet switch. I guess the first thing is to get a new cable. Any other suggestions?  

Nope, just a decent CAT5e cable to start with. If you still have problems with a new cable then we'll need the #1016/#1016x kernel logs to take things forward. If the new cable resolves the issue then it might still be worth having the logs - my plan is to ping them to a kernel developer familiar with the r8169, based on the assumption that the 4.19-rc1 kernel introduces some sort of regressive behaviour.  

I bypassed the switch and went directly from my computer into libreelec. I ran iperf:

Last login: Thu Nov  8 11:53:24 on ttys000
Johns-iMac-2:~ johnmerrill$ ssh [email protected]
[email protected]'s password: 
##############################################
#                  LibreELEC                 #
#            https://libreelec.tv            #
##############################################

LibreELEC (official): 8.2.5 (Generic.x86_64)
LibreELEC:~ # iperf -c 10.0.1.62 -t 60 -i10
Connecting to host 10.0.1.62, port 5201
[  4] local 169.254.59.221 port 46516 connected to 10.0.1.62 port 5201
[ ID] Interval           Transfer     Bandwidth       Retr  Cwnd
[  4]   0.00-10.00  sec  1.10 GBytes   941 Mbits/sec    0    257 KBytes       
[  4]  10.00-20.00  sec  1.10 GBytes   941 Mbits/sec    0    257 KBytes       
[  4]  20.00-30.00  sec  1.10 GBytes   941 Mbits/sec    0    257 KBytes       
[  4]  30.00-40.00  sec  1.10 GBytes   941 Mbits/sec    0    257 KBytes       
[  4]  40.00-50.00  sec  1.10 GBytes   941 Mbits/sec    0    257 KBytes       
[  4]  50.00-60.00  sec  1.10 GBytes   941 Mbits/sec    0    257 KBytes       
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Retr
[  4]   0.00-60.00  sec  6.57 GBytes   941 Mbits/sec    0             sender
[  4]   0.00-60.00  sec  6.57 GBytes   941 Mbits/sec                  receiver

iperf Done.
LibreELEC:~ # 

I then installed 1016 followed by 1016x and got this:

#10016
http://ix.io/1rla
#10016x
http://ix.io/1rlc

Just to make things interesting I ran #1107 which works fine, now. I'm going to try to figure out the problem with the switch. I have a Time Warner modem that connects via ethernet to an Apple base station. The ethernet runs from the Apple basestation as does the wireless. I will refigure that setup.