Also the speed is per lane, eg an x8 slot / port / device is called that because it has 8 lanes, which all transfer in parallel.
So... That's about 16 terabytes per second per lane. AKA more bandwidth than I can imagine any use for, though I'm sure we will find ways to take advantage...
(Seriously, that's enough to move 16 largish laptop drives every second, on a single lane.)
Though the exact details of the overhead don't matter very much. They add 6% extra bits, good enough.
The part I want to call out as complicated/confusing is that a PCIe 7.0 lane puts out a voltage 64 billion times per second, but because each voltage is based on two bits that counts as 128 billion "transfers".
Actually at that point, a pcie7 nvme would be faster than ddr6
https://www.pcworld.com/article/2237799/ddr6-ram-what-you-sh...
That said, per-pin, 16GB/s seems to be the same ballpark as contemporary (to pcie7) main or graphics memory..... Like, actually more if I'm reading this right?
https://www.anandtech.com/show/21287/jedec-publishes-gddr7-s...
Is non-ISO unit "T" / "transfer" a marketing term or really specialised jargon? "transfer" just doesn't click in my mind, at best "a transfer" (countable) is about moving a sizeable aggregate chunk that has some semantic meaning, not a single fundamental quantum of information.
Unrelated: "gigatesla per second" is such a mind-boggling unit.