Comment by kev009

AFAIK those sold relatively well, considering the TCO of both sides (NICs were very expensive and there were like a dozen companies vying for position once upon a time). They were also interesting because they were cut-through. CX4 was noticeably lower latency than SFP+. So a very fast, but feature limited architecture which is probably why other players like Cisco and then Arista (aka Broadcom) took over.