I've been trying for days now to understand why I can't get over 500 mbps while connected on my unRAID server over wireguard. The unRAID server has a symmetrical 1 gbps connection and the client has a 1 gbps down/100 mbps up connection. When I try to download a big file using SMB from my client, there is a hard cap at about 450-500 mbps.

Things I tried:

- tried Tailscale, as it's using Wireguard the result is the same, maybe slightly less.

- played with MTU settings -> didn't seem to make a difference, I tried to go from 1320 to 1420 without huge gains/changes

- tried to enable/disable SMB multichannel, didn't make a difference

- iperf3 somehow caps at 10 MB/s which is around 80 mbps, even when I set it with the -R flag (this means that my server actually sends data to the client, I expect this to be full gigabit). Here are the results of the iperf3 test both with and without -R.

- using multiple streams during iperf3 test shows pretty much the same results

- this iperf3 result confuses me because I am able to download files at 500 mbps from the server and it's not capped at 85 mbps as the iperf3 test shows

 

- The unraid server specs are the following:

N5105, 16 gb ram, 4 2.5 gbps nic (i226-v) -> during the download none of the cpu cores are at 100%, the load is pretty evenly distributed between the cores

- I tried multiple clients, every one of them caps at that limit.

 

Thank you very much for any kind help or tip!

 

iperf3.exe -c 192.168.178.73

Connecting to host 192.168.178.73, port 5201

[ 4] local 10.253.0.2 port 50836 connected to 192.168.178.73 port 5201

[ ID] Interval Transfer Bandwidth

[ 4] 0.00-1.00 sec 8.12 MBytes 68.0 Mbits/sec

[ 4] 1.00-2.01 sec 8.25 MBytes 68.7 Mbits/sec

[ 4] 2.01-3.00 sec 9.00 MBytes 75.9 Mbits/sec

[ 4] 3.00-4.01 sec 9.62 MBytes 80.5 Mbits/sec

[ 4] 4.01-5.01 sec 8.75 MBytes 73.3 Mbits/sec

[ 4] 5.01-6.01 sec 9.25 MBytes 77.4 Mbits/sec

[ 4] 6.01-7.02 sec 8.50 MBytes 71.0 Mbits/sec

[ 4] 7.02-8.00 sec 8.50 MBytes 72.1 Mbits/sec

[ 4] 8.00-9.00 sec 8.25 MBytes 69.5 Mbits/sec

[ 4] 9.00-10.00 sec 10.9 MBytes 91.2 Mbits/sec

- - - - - - - - - - - - - - - - - - - - - - - - -

[ ID] Interval Transfer Bandwidth

[ 4] 0.00-10.00 sec 89.1 MBytes 74.8 Mbits/sec sender

[ 4] 0.00-10.00 sec 89.1 MBytes 74.8 Mbits/sec receiver

 

and

iperf3.exe -c 192.168.178.73 -R

Connecting to host 192.168.178.73, port 5201

Reverse mode, remote host 192.168.178.73 is sending

[ 4] local 10.253.0.2 port 50838 connected to 192.168.178.73 port 5201

[ ID] Interval Transfer Bandwidth

[ 4] 0.00-1.00 sec 9.38 MBytes 78.7 Mbits/sec

[ 4] 1.00-2.00 sec 9.72 MBytes 81.4 Mbits/sec

[ 4] 2.00-3.00 sec 10.0 MBytes 84.0 Mbits/sec

[ 4] 3.00-4.00 sec 10.1 MBytes 84.7 Mbits/sec

[ 4] 4.00-5.00 sec 10.4 MBytes 87.4 Mbits/sec

[ 4] 5.00-6.00 sec 10.2 MBytes 85.2 Mbits/sec

[ 4] 6.00-7.00 sec 9.83 MBytes 82.5 Mbits/sec

[ 4] 7.00-8.00 sec 10.0 MBytes 84.1 Mbits/sec

[ 4] 8.00-9.00 sec 10.0 MBytes 84.2 Mbits/sec

[ 4] 9.00-10.00 sec 10.4 MBytes 87.6 Mbits/sec

- - - - - - - - - - - - - - - - - - - - - - - - -

[ ID] Interval Transfer Bandwidth Retr

[ 4] 0.00-10.00 sec 101 MBytes 85.1 Mbits/sec 0 sender

[ 4] 0.00-10.00 sec 100 MBytes 84.2 Mbits/sec receiver

 

Up? Iperf3 result now match but I am still stuck at around 500-550 mbps. Thank you