It sounded to me like they were extrapolating though, "This resulted in a ~100ms improvement on a fast machine with an SSD but, since most of this work was I/O

It sounded to me like they were extrapolating though, "This resulted in a ~100ms improvement on a fast machine with an SSD but, since most of this work was I/O bound, we expect it to be even more noticeable on slower hardware." This in fact was where I drew the inspiration for my comment from.