All I know is when I changed out 458 to the direct drive it moves a noticeably more air on low than the old fan did.
I am sure it does as I felt air rushing past my head while I was playing with the speed switch! I guess it being so much quieter, makes me "think" it's not the same although the CFM specs say it is. I love this upgrade and never have to worry about a belt slipping off or the noise!