CFM is a measure of volume moved, generally quoted at effectively zero static pressure. Zero static pressure is rarely reality. All fans will have a static pr

CFM is a measure of volume moved, generally quoted at effectively zero static pressure. Zero static pressure is rarely reality. All fans will have a static pressure vs airflow curve, which will vary based on the design of the fan. I doubt normal people have the tools to measure fan CFM, especially when mounted into a product or enclosure, so presumably the OP was going based on stated specs.