I'm afraid it was 2+ years ago so I don't remember, but it must have been slower than the comparable speed from the gigabit wired connection. FWIW, I was so happy with the Sonnet (not as hot as some alternatives I've used) that I bought two more. However, unless you are using fiber or for other reasons preferring SFP+, going with the grain and getting 10Gbase-T is probably easier.
Getting back to the OP, this could be interesting for me if and only if I can get fiber based Thunderbolt-4, but it seems to not yet be available.
Thanks. $528 for 30 meter TB3 compared to $35 for 30 meter OM4 and a pair of $10 10G SFP+ modules (and the same OM4 will carry 25GbE just fine). Seems like it's not really cost effective.
Getting back to the OP, this could be interesting for me if and only if I can get fiber based Thunderbolt-4, but it seems to not yet be available.