It would be 40 gigabits per second, and I hadn't even noticed the capital B (which I assume was a typo) until you pointed it out. I was about to say that this

It would be 40 gigabits per second, and I hadn't even noticed the capital B (which I assume was a typo) until you pointed it out. I was about to say that this is a consistent convention for networking to use bits instead of bytes, but I realized this breaks down with something like IB that has been used as a bus-like interconnect and a storage network/fabric (both areas where bytes are the more common convention in rates). Even today, 40 gigabytes per second would be pushing the I/O capacity of a typical Xeon, though not a 128-lane Epyc, and I'm not sure about POWER9. With 200Gb/s IB with both bandwidth and latency on the same OOM as other-socket RAM, it's also pretty close to pushing that capacity, which is, of course, the whole point, I suppose.