Well, it's possible that the IO is dispatched from a single thread but can be handled in parallel by the OS. If the single thread doesn't need to block, it nee

Well, it's possible that the IO is dispatched from a single thread but can be handled in parallel by the OS. If the single thread doesn't need to block, it needn't be the bottleneck. Still, even if they are somehow seeing 100x speedup, it won't be because 100 threads are near constantly busy - without that many cores (after hyperthreading, maybe, with caveats) it is simply not going to be the case that all threads are constantly busy.