any fan can be any cfm ?? look up your fans specs .
you can have a fan that's 3000rpm and say 30 cfm or you can have one that's 3000rpm and 104 cfm . 0r one that's 1600 rpm at 30cfm or 1600 at 104 ??
it all in the blade design and housing like acting with a shroud affect what ever , the fan manufacture designs / engineers the fans to fit a speced need at any given rpm to produce any CFm rating
like I showed here
''the stock fan is 104 cfm@2000 rpm the replacement fan is 158 cfm @3000 rpm should be fine just about = same cfm per rpm [ .053 per 1 rpm .053 x 3000 = 159 0r .053 x 2000 = 106 ''rounded off '' .05266666.....]
so them 2 fans even not speced the same shows thy do the same work [cfm] pre rpm used so at 2000 rmps the 3000 rpm fan has the near same cfm at 2000 rpm when at that speed or any speed
so that helps when you need to know so you don't replace a 104cfm rated fan with one that a 30 cfm fan and find things aint cooling proper cause its nott doing the job cause its not moving enough air around as required for the task
3000 RPM 6 CFM
https://www.newegg.com/Product/Product.aspx?Item=9SIA85V36V6249
3000 RPM • 36.48 CFM
https://www.newegg.com/Product/Product.aspx?Item=N82E16835119125
3000-3499 RPM >80 CFM
https://www.newegg.com/Product/Product.aspx?Item=9SIA6G73YE7824
what ever your need requires??