Well the box is different! But jokes aside, Noctua has some amazing packaging as usual with folding flaps on the front and back giving you information about the fan and the tech involved.
When we look at the numbers given for the airflow and pressure we can see the old model has less airflow but more static pressure. This has to do with the new design, the new models still have the trued and tested have Noctua’a AAO frame (Noctua’s AAO Advanced Acoustic Optimization) that include silicone rubber vibration absorbers on all corners, the stepped inlet and little golf ball dimples on the sides.
But the newest invention is the Anti-Stall Knobs, let me quote that for you.
Noctua’s S12 series impellers use a high angle of attack in order to achieve superior airflow. However, impellers with high angles of attack are typically more prone to undesired stall and flow separation phenomena that can occur when the fan is working against higher impedance such as when blowing through tight fan filters or when used on heatsinks and radiators.
In these situations when the fan is building up high pressure but less air is moving through, the speed of the air particles flowing alongside the suction side of the fan blades gradually decreases towards the trailing edge.
The lower the speed and the higher the counter-pressure, the higher the risk of the air particles becoming detached from the blade surface. This flow separation phenomenon known as stall leads to undesired turbulence, reduced efficiency and translates into a dent in the fan’s performance curve.
