Poor speed with Chelsio T420-CR
I have a Chelsio T420-CR 10gbe NIC in a Supermicro A1SRi-2758f based pfsense router. I get poor speed (~1.2gbps) testing between the router and the desktop. The desktop has a Mellanox ConnectX-2 SFP+ card. The pfsense was setup with no customization with a WAN and a LAN (no packages installed).
The pfsense router was then wiped and replaced with FreeBSD-11. Testing again with the desktop, iperf3 this time showed ~9.5gbps speed as expected. Incidently, pfSense-2.4 snapshot also gives poor speed. I also booted the pfSense router in Arch Linux and again got ~9.5gbps speed.
It seems something is holding back T420-CR card in pfSense which is not an issue in FreeBSD-11.