I run OpnSense in an XTM5 second gen. It works beautifully.
This hardware comes with a Nitrox CAvium Card to accelerate VPN crypto
It appears drivers were released for linux:
https://github.com/torvalds/linux/tree/master/drivers/crypto/cavium/nitrox
Does it means someone could support that card in OpnSense ?
Someone indeed could to that. Because it is software and someone could port that driver over to FreeBSD or check if there is one already.
The NITROX III Series seem to come with a FreeBSD driver. But they talk about 1024bit or 2048bit. Not what I would use.
What would be the benefit for someone to do this work?
Less Tax on CPU for vpn encryption, decryption.
What bandwidth do you push over the VNP?
With AES-NI in my understanding you get similar things free for "normal" bandwidth usage.