![Noctua Cooling Fans | Noctua Fan A4x20 | Noctua Nf A4x10 | Noctua Fan 12v | Noctua Fan 4 - Case Fans - Aliexpress Noctua Cooling Fans | Noctua Fan A4x20 | Noctua Nf A4x10 | Noctua Fan 12v | Noctua Fan 4 - Case Fans - Aliexpress](https://ae01.alicdn.com/kf/H5a2c6881c30541a09fac9f7d76d504f7z/Noctua-NF-A4x20-FLX-4cm-fan-20mm-Cooling-fan-5V-12V-and-3pin-4pin-PWM-thickness.jpg)
Noctua Cooling Fans | Noctua Fan A4x20 | Noctua Nf A4x10 | Noctua Fan 12v | Noctua Fan 4 - Case Fans - Aliexpress
![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 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](https://preview.redd.it/iowcxp3hjsh51.jpg?auto=webp&s=3ada0ae8b6e0b5df99650b5a7fecdb2c8ed3e30e)
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 Cooling Fans | Noctua Fan A4x20 | Noctua Nf A4x10 | Noctua Fan 12v | Noctua Fan 4 - Case Fans - Aliexpress Noctua Cooling Fans | Noctua Fan A4x20 | Noctua Nf A4x10 | Noctua Fan 12v | Noctua Fan 4 - Case Fans - Aliexpress](https://ae01.alicdn.com/kf/S9e7c301f2eed499ab5cea3bc27593d59E/Noctua-NF-A4x20-FLX-4cm-fan-20mm-Cooling-fan-5V-12V-and-3pin-4pin-PWM-thickness.png)