Question regarding Cfm

[Louis531]

Hey guys Im thinking of getting some thermaltake riing fans for my mastercase pro 5 as intake fans. I understand these fans are not optimized for airflow but it looks very nice. Since they are not optimized for airflow, here is the question:
Should I get 120mm variant which has 51 cfm or 140mm which has 40cfm? Because I have read that larger fan is able to produce more airflow at lower noise, but then this 120mm riing fan has higher cfm. Which one I should be getting for more airflow?
Sorry for bad English.

 

[rolli59]

cfm (cubic feet min) means airflow so apparently the 51 on the 120mm is more airflow than the 40 on the 140mm which is quieter because it turns slower rpm.

 

[Louis531]

cfm (cubic feet min) means airflow so apparently the 51 on the 120mm is more airflow than the 40 on the 140mm which is quieter because it turns slower rpm.

Thanks for prompt reply