Amdahls law is about coordination costs, so either you would expect cores to be starved or lots pf extra coordination-related compute to be happening, which, i

Amdahls law is about coordination costs, so either you would expect cores to be starved or lots pf extra coordination-related compute to be happening, which, i guess is not totally crazy since there are that many crates, but as a first guess OP's back of the envelope is fine