Iperf3 issue

Hardware Hub Networking
1

so setting truenas as server and making a connection test from windows computer to truenas iperf3 server instance nets 9+ Gbit/sec however when running in reverse with -R parameter I see 4Gbit/sec. I am not sure what is causing the decline for recieving parameter. Any ideas? Linux box show 9 and 9 for both.

The setup is a windows machine with a ASUS 10gbit aquantia card, truenas is intel 10gbit card, and switch between them is a mikrotik 10gbit switch.

One direction is the correct bandwidth the other is half.

Not sure where to start. I would rather run this without mtu of 9000 which might fix the issue, but break other devices that cant do 9000 mtu.

2

Double check what iperf3 build you are using. I remember vaguely that on windows ancient or weirdly compiled build were in circulation and caused issues (cygwin dlls?).

There was supposedly less problematic build somewhere, but most people recommended to not use iperf on windows, or accept strange results.

3

I still see on transmit at 9gbit but recieve is 5gbit.