Noctua NF-A12x25 Fan Review

👤by Matthew Hodgson Comments 📅17-05-18
Closer Look (PWM, FLX, ULN)
Noctua have decided on a 9-blade arrangement to their fan, with small Flow-Acceleration Channels on the blades to help improve airflow and reduce noise. You may notice the odd, textured look to the blades, which is a result of the Sterrox Liquid-Crystal Polymer compound that Noctua use. This material presents many desirable properties, such as extreme tensile strength, low thermal expansion coefficient and damping characteristics that reduce resonance and vibration, therefore reducing noise.

The tensile strength and low thermal expansion are both incredibly important, allowing Noctua to run the outer tip of the blades within 0.5mm of the inside wall of the housing.
Typically, a fan would run a tolerance of around 1.5mm and up to 4mm in some budget fans. Running the blades this close to the inner edge helps the fan work against back pressure by reducing leaking between the impeller and frame.



The frame is also cleverly designed, which Noctua call AAO (Advanced Acoustic Optimisation). This plastic is chosen for its ability to absorb sound and vibration effectively. Other proprietary techniques are involved here, with a stepped inlet and inner surface design choices which help to further refine the fans noise and performance.

The central hub of the fan is made from a solid piece of steel, with a CNC milled brass shell in the centre. The hub runs on an SSO2 bearing, an evolution of the tried and tested SSO bearing used in previous fans. The rear magnet is placed closer to the axis to provide better stability, precision and durability over time.



Anti-vibration pads are included on all corners, which can be removed if you so wish, however we would obviously recommend these remain in place. If the fan is in direct contact with your case, the fan can transmit vibrations and therefore noise into the metal structure of your system chassis. When using the fans on a radiator, its important that all of the air is pushed through the fins, and not around the outside, therefore Noctua have included a gasket, which replaces the 4 anti-vibration pads and creates a seal against the radiator, thus improving airflow which in turn can reduce temperatures and noise.



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