20.7.3 vmxnet 10Gbps adapter via tagged VLAN slow performance

[Archanfel80]

Hi!

I have multiple opnsense virtual machine with vmxnet adapter's. All of them is 10Gbps connection.
The internet access is 1/1 Gbps. I can measure when im directly connected to with my laptop.
I use 802.1q vlan tagging on the virtual machines using simply static ip addressing.
Every opnsense vm produce the symptoms like the bandwidth reduced to around 600/600Mbps.
This issue only occured since upgrade to 20.7. It was fine with the 20.1.
My friends also experiencing this issue, it seems its some kind of overhead because we experienced this:
1000/1000 connection measured around 600/600
500/500 connection measured around 300/300
300/300 connection measured arounf 200/200

Non of them is pppoe so its not mtu issue. We use the standard 1500byte on everywhere.
If i put a soho mikrotik device instead of the opnsense it can be translate the full gigabit without an issue.
Anybody knows anything about this?

update: its the same result with e1000e adapter too using vmware.
update: using proxmox with virtio works fine.
update: the same setup working perfect with pfsense which is based on Freebsd 11 not HBSD.
It seems the HBSD is the source of all problems...

Thx!

[Gauss23]

There is a discussion going on about this topic:
https://forum.opnsense.org/index.php?topic=18754.0