I decided to run a few tests just to provide a point of reference with what I have. The files are being served from an old Sandybridge Win10 Pro box with a single gigabit NIC. The network between devices is a couple Unifi gigabit switches. The OSMC device is Vero 4K (not plus) running 3.14 staging with relevant settings, including the buffers, in a stock configuration.
Iperf tests
Built-in fast ethernet adapter
Summary
osmc@Vero:~$ iperf3 -R -c 192.168.254.201
Connecting to host 192.168.254.201, port 5201
Reverse mode, remote host 192.168.254.201 is sending
[ 4] local 192.168.254.106 port 36281 connected to 192.168.254.201 port 5201
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 11.5 MBytes 96.6 Mbits/sec
[ 4] 1.00-2.00 sec 11.3 MBytes 94.9 Mbits/sec
[ 4] 2.00-3.00 sec 11.3 MBytes 94.9 Mbits/sec
[ 4] 3.00-4.00 sec 11.3 MBytes 94.7 Mbits/sec
[ 4] 4.00-5.00 sec 11.3 MBytes 94.9 Mbits/sec
[ 4] 5.00-6.00 sec 11.3 MBytes 94.9 Mbits/sec
[ 4] 6.00-7.00 sec 11.3 MBytes 94.9 Mbits/sec
[ 4] 7.00-8.00 sec 11.3 MBytes 94.9 Mbits/sec
[ 4] 8.00-9.00 sec 11.3 MBytes 94.9 Mbits/sec
[ 4] 9.00-10.00 sec 11.3 MBytes 94.9 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-10.00 sec 114 MBytes 95.2 Mbits/sec sender
[ 4] 0.00-10.00 sec 114 MBytes 95.2 Mbits/sec receiver
iperf Done.
osmc@Vero:~$ iperf3 -c 192.168.254.201
Connecting to host 192.168.254.201, port 5201
[ 4] local 192.168.254.106 port 36283 connected to 192.168.254.201 port 5201
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 12.5 MBytes 105 Mbits/sec 0 215 KBytes
[ 4] 1.00-2.00 sec 11.6 MBytes 97.5 Mbits/sec 0 269 KBytes
[ 4] 2.00-3.00 sec 11.3 MBytes 95.1 Mbits/sec 0 269 KBytes
[ 4] 3.00-4.00 sec 11.4 MBytes 95.4 Mbits/sec 0 271 KBytes
[ 4] 4.00-5.00 sec 11.2 MBytes 94.1 Mbits/sec 0 271 KBytes
[ 4] 5.00-6.00 sec 11.3 MBytes 95.1 Mbits/sec 0 271 KBytes
[ 4] 6.00-7.00 sec 11.3 MBytes 94.8 Mbits/sec 0 271 KBytes
[ 4] 7.00-8.00 sec 11.3 MBytes 95.0 Mbits/sec 0 271 KBytes
[ 4] 8.00-9.00 sec 11.3 MBytes 94.9 Mbits/sec 0 271 KBytes
[ 4] 9.00-10.00 sec 11.3 MBytes 95.2 Mbits/sec 0 271 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth Retr
[ 4] 0.00-10.00 sec 115 MBytes 96.2 Mbits/sec 0 sender
[ 4] 0.00-10.00 sec 113 MBytes 95.1 Mbits/sec receiver
Amazon USB 3.0 gigabit adapter
Summary
osmc@Vero:~$ iperf3 -R -c 192.168.254.201
Connecting to host 192.168.254.201, port 5201
Reverse mode, remote host 192.168.254.201 is sending
[ 4] local 192.168.254.190 port 34395 connected to 192.168.254.201 port 5201
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-1.00 sec 451 KBytes 3.70 Mbits/sec
[ 4] 1.00-2.00 sec 20.0 MBytes 167 Mbits/sec
[ 4] 2.00-3.00 sec 25.4 MBytes 213 Mbits/sec
[ 4] 3.00-4.00 sec 25.8 MBytes 216 Mbits/sec
[ 4] 4.00-5.00 sec 25.7 MBytes 216 Mbits/sec
[ 4] 5.00-6.00 sec 25.8 MBytes 216 Mbits/sec
[ 4] 6.00-7.00 sec 22.6 MBytes 189 Mbits/sec
[ 4] 7.00-8.00 sec 19.7 MBytes 165 Mbits/sec
[ 4] 8.00-9.00 sec 17.8 MBytes 149 Mbits/sec
[ 4] 9.00-10.00 sec 25.2 MBytes 212 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth
[ 4] 0.00-10.00 sec 209 MBytes 175 Mbits/sec sender
[ 4] 0.00-10.00 sec 209 MBytes 175 Mbits/sec receiver
iperf Done.
osmc@Vero:~$ iperf3 -c 192.168.254.201
Connecting to host 192.168.254.201, port 5201
[ 4] local 192.168.254.190 port 34397 connected to 192.168.254.201 port 5201
[ ID] Interval Transfer Bandwidth Retr Cwnd
[ 4] 0.00-1.00 sec 22.1 MBytes 186 Mbits/sec 0 69.9 KBytes
[ 4] 1.00-2.00 sec 22.3 MBytes 187 Mbits/sec 0 72.7 KBytes
[ 4] 2.00-3.00 sec 22.3 MBytes 187 Mbits/sec 0 72.7 KBytes
[ 4] 3.00-4.00 sec 22.3 MBytes 187 Mbits/sec 0 72.7 KBytes
[ 4] 4.00-5.00 sec 22.3 MBytes 187 Mbits/sec 0 75.6 KBytes
[ 4] 5.00-6.00 sec 22.3 MBytes 187 Mbits/sec 0 77.0 KBytes
[ 4] 6.00-7.00 sec 22.3 MBytes 187 Mbits/sec 0 77.0 KBytes
[ 4] 7.00-8.00 sec 22.3 MBytes 187 Mbits/sec 0 81.3 KBytes
[ 4] 8.00-9.00 sec 22.3 MBytes 187 Mbits/sec 0 84.1 KBytes
[ 4] 9.00-10.00 sec 22.3 MBytes 187 Mbits/sec 0 84.1 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth Retr
[ 4] 0.00-10.00 sec 223 MBytes 187 Mbits/sec 0 sender
[ 4] 0.00-10.00 sec 223 MBytes 187 Mbits/sec receiver
Playback tests
To evaluate playback I used the 10 bit HEVC jellyfish bitrate test files and watched Kodi’s video debug display to find when skipped frames started occurring and when the buffer had issues staying full. As such tweaking buffer settings may lead to better results, but this was the least subjective, and easiest repeatable way I could think to run this kind of test.
Built-in NIC Kodi SMB path: Perfect up to 40mb/s jellyfish. 60mb/s jellyfish inconsistent (sometimes played perfect, sometimes lots of skipped frames), 90mb/s jellyfish skipped frames.
Built-in NIC SMB system mount: Perfect up to 60mb/s jellyfish, but had trouble maintaining buffer. 90mb/s jellyfish skipped frames.
Amazon USB 3.0 gigabit adapter Kodi SMB path: Perfect up to 60mb/s jellyfish. 90mb/s jellyfish skipped frames.
Amazon USB 3.0 gigabit adapter SMB system mount: Perfect up to 90mb/s jellyfish. 120mb/s jellyfish almost perfect, had trouble filling buffer, sometimes a couple skipped frames.