I wanted to upgrade my stock part cooling fan to a pair of noctua 40mm fans and when I did a test run they barely push any air through the ducts compared
Noctua pc冷却ファン,コンピューターケースおよびタワー,NF A4x20 x 40x20mm,flx 40mm,5000 rpm,14.9 db (a)|Fans & Cooling| - AliExpress