[ste2425]

This is probably a short question but I'm looking to upgrade my very old fan collection to something that can still provide good cooling but doesn't turn my computer into a jet engine. My current fans are the same ones I bought when building my first pc and lets say I went for looks in choosing them and whilst my knowledge on the rest of my computer has grown I still have no idea about fans. I understand the dB ratings but the CFM is it for airflow. I have no reference so when I see fans stating this that and the other I have to idea if that's actually any good or not.
Hope you lot can just give a reference as to what level of CFM will provide good cooling. Thanks all