Which fan is right for me?

With the NF-S12B and NF-P12, Noctua provides two premium-class fans which have been optimized for specific fields of application. Choosing the appropriate model can therefore help you to obtain even better results. Nevertheless, both the NF-S12B and NF-P12 achieve good results in virtually all typical applications. So in case you aren't sure which of the two fans is right for you: Don't worry, you can't go wrong with either of the two!

We principally recommend the NF-S12B for the following applications:

Case ventilation (with the exception of very restrictive fan grills, filters or significant obstruction to airflow)
CPU coolers with wide fin-spacing
Water-cooling radiators with wide fin-spacing
All applications where minimum noise emission has first priority

We principally recommend the NF-P12 for the following applications:

CPU coolers with tight fin-spacing
Water-cooling radiators with tight fin-spacing
Power supplies
Storage solutions
Cases with very restrictive fan grills and filters
All applications with significant obstruction to airflow

Links:

NF-S12 & NF-P12: Technical Backgrounds