alright, I'll tell you straight out, almost every company that makes case fans lies through their teeth about either the CFM or the dba, most times, both, I can only suggest the one company's figures that I trust, known for being some of the most quiet, well-performing fans in CFM:noise ratio that are in use today, recommended extensively,
the Yate Loon D12SL-12 's.
this particular vendor sells pre-sleeved D12SL-12 fans, which I think is relatively convenient.