Pressure-optimised or airflow-optimised fan for rear exhaust?

[King Mustard]

I currently have a be quiet! Shadow Wings 2 (120mm, 39 CFM, 450-1100 RPM, PWM) as the exhaust for my PC .

Whilst it's very quiet, it doesn't seem to be extracting a lot of heat out of the system. Presumably, this is due to it having a 39 CFM peak.

Therefore, I am trying to decide between the Noctua NF-F12 PWM and the Noctua NF-S12A PWM.

This Noctua page suggests:

"NF-F12 is a pressure-optimised fan that excels on heatsinks and radiators and the NF-S12A is an airflow-optimised fan that provides excellent results as a case fan and in other low- to mid-impedance applications."

Presumably, I'll want to go for the NF-S12A then, but I thought I'd check with you all first.

Full system details.

[kalniel]

Yep, their explanation is straightforward and you've interpreted it correctly - airflow is what you want for case extraction.

[CAT-THE-FIFTH]

Pressure optimised can be useful for inlet fans,if there is a lot of stuff in the way,ie,HDD drive bays,etc. For the exhaust you would want airflow optimised fans.

[Ttaskmaster]

If you're set on Noctua, get the A12 fan. It generally spanks every one of their other models.
Personally I use Corsair ML120s throughout my system.

[CAT-THE-FIFTH]

I use the 15MM slim version of the A12 myself in my SFF system,and they have been pretty decent so far.

[ik9000]

SFAIK the only time you want pressure optimised on an exhaust is if it's pushing through a radiator at the same time. That said you can get some fans that are good at both so then it's a no-brainer.