The Internet forums would have you believe that USB-based ethernet adaptors aren’t good enough if you’re performance conscious. I’m planning to deploy an Intel NUC mini-PC as a home router/firewall. NUCs only have one ethernet adaptor built in, but have USB3 ports.

I naturally wanted to find out what performance I might be sacrificing if I used a USB3 port as the second LAN port on the NUC, so I got an Anker-branded USB3 to Ethernet adaptor, plugged it into a laptop, and configure iperf3 as a server on my desktop.

Connecting to host 192.168.1.125, port 5201
[  4] local 192.168.1.98 port 54918 connected to 192.168.1.125 port 5201
[ ID] Interval           Transfer     Bandwidth
[  4]   0.00-1.00   sec   106 MBytes   886 Mbits/sec                  
[  4]   1.00-2.00   sec   104 MBytes   871 Mbits/sec                  
[  4]   2.00-3.00   sec  93.5 MBytes   784 Mbits/sec                  
[  4]   3.00-4.00   sec   106 MBytes   886 Mbits/sec                  
[  4]   4.00-5.00   sec   103 MBytes   866 Mbits/sec                  
[  4]   5.00-6.00   sec   102 MBytes   858 Mbits/sec                  
[  4]   6.00-7.00   sec   106 MBytes   886 Mbits/sec                  
[  4]   7.00-8.00   sec   104 MBytes   873 Mbits/sec                  
[  4]   8.00-9.00   sec   108 MBytes   908 Mbits/sec                  
[  4]   9.00-10.00  sec   111 MBytes   931 Mbits/sec       

The performance speaks for itself. It works just as good as the built-in ethernet card.

Don’t be swayed by vague claims about the suitability of USB ethernet adaptors for use in homebrew routers. They seem fine for the task.