I think noctua fans are just better fans, noisewise.

They have better airflow design and sound dampening/isolating screw mounts.

I think the idea about reduced airflow might be backwards - most systems use PWM to spin the fans based on CPU or system temperature. This means the systems get the airflow they need.

Also, they make larger heatsinks + fans for certain systems that allow the same airflow using a larger, slower spinning fan. which means less sound.

that said, there are some noctua fans that can spin faster than others.