You're right, EFA is custom nitro NICs. Although Mellanox (now Nvidia ConnectX) is not solely Inifiband either - Nvidia offers them with Ethernet upto 400GbE as

You're right, EFA is custom nitro NICs. Although Mellanox (now Nvidia ConnectX) is not solely Inifiband either - Nvidia offers them with Ethernet upto 400GbE as well, same speed as EFA says on the label.