I flashed one of mine (and lost my notes; took three hours to do and find a verifably correct image, five minutes to do, one second to forget to save the goddamn text file, so thank you) which gave me RDMA a while back, and to the best of my recollection, it worked, but when I reinstalled it this week, despite showing enabled in Powershell, it was not doing RDMA transfers (other side was a ConnectX-3, so no issue there) most obviously because I was tracking my speed in Task Manager/Resource Monitor.
Also, despite some peaks at 6/7Gbps, I was usually seeing 170MB/s on a single SMB Live Migration, but in the past 4+Gbps has been my usual speed (also not a disk issue; I was able to push the transfer higher by doing multiple Live Migrations, but I stayed at 800-1500Mbps EDIT: *per VM migration* e.g. 4Gbps with 3 or 4 running). Most of my VMs are 10-20GB, so it's an annoyance there, but I do have one 220GB VM which also does 500KB/s in db writes, so that is... problematic, not least of all because it has my UBNT mFi server, several months of electrical power usage logs... and acts like a "soft" circuit breaker, cutting mains to UPSes upon surges (like my fridge spiking at 800W or running at 450W for 15 minutes for no obvious reason) which protects 2/3rds of my LAN.
I just installed two more of these, and probably will add my fourth and final card in, so first off, thank you again for the notes, but yes, this just became more important to me, especially as I moved off my Brocade 1020s specifically to get RDMA... also I'd love to get rid of the "QOS (ETS) capability is missing" error in my logs.
So if people could mention which (and where they got) firmwares that are doing well in TCP and SMB3+RDMA performance here, I'm sure I wouldn't be alone in being very grateful.