Comparing vacuum pumps

[j17henry]

Looking at two different pumps that use two different ways to measure what they are capable of. 7.5 hp busch mink 1252 av says 170 acfm and 150 torr.
The othe pump is republic 17 hp regenerative pump 13” of static 335 cfm.
Seams like the 17 hp pump would be capable of a lot more than a 7.5 but not sure of the difference in cfm and acfm.