XCPNG and TrueNAS via 10G NICS only communicating 1G


I have a problem communicating at 10G between xcpng 8.2.1 (via Broadcom 10G NIC) and TrueNAS-SCALE-22.12.1 (via Chelsio T540-CR). Both ends are direct connect without a switch between them - xcp at and truenas at, and also both set to mtu 9000 but when running iPerf3 I only get 1G throughput (as shown below)???

Anyone come across this who can provide some insight?


10gbps ~= 1.2 gBps

Your NIC is working at 10 gig

Thank you, but shouldn’t the SUM of bandwidth at the bottom state anywhere close to between 8-10GB???

I use the following command iperf3 -4 -P 10 -f G -c and the results shown:


Sam, you have a 10G connection that means 10G bits per sec.
Simply divide by 10 and you get 1G bytes per sec. (actually 1.15 GBytes/sec)

Agree, you’re confusing bits and Bytes. If it was a 1Gbps connection then iPerf would max out about 120MBps.

Duh, thank you for bringing this to my attention…been staring at my my screen for too long :frowning:

Thanks again,