Noctua NF-A12X25 G2 PWM 120mm Dual Fan Pack

The Noctua NF-A12X25 G2-PWM-SX2-PP Fans deliver superior performance and outstanding quietness of operation while providing superb smoothness and excellent long-term stability. Featuring a set of two fans offset in speed, optimising push-pull operation. With an overhauled blade and motor design, a major boost in noise efficiency, highly optimised P/Q curve for all applications, flow acceleration channels for better efficiency, AAO frame for improved acoustics, and integrated anti-vibration pads, these Noctua fans are a highly optimised cooling solution.

Features

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Noctua NF-A12X25-G2-PWM-SX2-PP Fan

The NF-A12x25 G2 PWM Sx2-PP is a set of two NF-A12x25 G2 PWM 120mm fans that are offset in speed, which can be beneficial in push-pull operation as well as in situations where two or more fans are operating side by side, such as in case cooling applications or on 240 and 360mm water cooling radiators. When two fans are running at almost the same, constant speed in a push-pull configuration or, albeit to a lesser extent, side by side, their acoustic interaction can lead to undesirable harmonic phenomena such as intermittent vibrations or periodic humming due to interference, which can be heard as beat frequencies. Therefore, the two NF-A12x25 G2 PWM fans contained in the Sx2-PP set are slightly offset in speed (+/- ~50rpm) in order to avoid such phenomena. This fine-tuning is made possible by the fans’ novel etaPERF™ motor and its NE-FD6 driver IC that achieves extremely precise speed control and, thanks to its SupraTorque™ feature, can leverage extra torque headroom to keep the exact desired speed even when working against significant flow resistance such as on water cooling radiators and heatsinks. With one fan running ~50rpm slower (PPA) and one ~50rpm faster (PPB), the overall cooling performance can be kept the same while efficiently preventing intermittent vibrations or periodic humming. Since the perception of beat frequencies can vary depending on psychoacoustic preferences, users can easily further optimise acoustics by slowing the PPA fan down a little more through PWM control or the supplied Low-Noise-Adaptor, which will result in an even smoother sound signature due to the increased offset. If more than two fans are running side by side, customers can either combine multiple Sx2-PP sets or add a single NF-A12x25 G2 PWM fan and reduce its speed to the level of the PPA model (~1750rpm) using PWM control in order to make sure that neighbouring fans are never running at the same speed.

Next-Generation Performance

Building upon the success of the original NF-A12x25, the G2 version introduces a refined blade geometry and a novel motor design. These advancements lead to a significant boost in performance-to-noise efficiency, allowing the NF-A12x25 G2 to achieve superior results across various applications, including water cooling radiators, heatsinks, and case fan setups.

Dual Fan Set for Push-Pull and Side-by-Side Usage

Bundling two NF-A12x25 G2 PWM fans that are speed-offset by +/- ~50rpm in order to avoid undesired acoustic interaction phenomena, the Sx2-PP set is the ideal choice for push-pull configurations as well as situations where two or more fans are operating side by side such as on 240 and 360mm radiators or in typical case cooling applications.

Speed-Offsetting Three or More Fans

If more than two fans are running side by side, Sx2-PP sets can be combined to avoid situations where two neighbouring fans run at the same speed level. If the total number of fans is uneven such as when equipping a 360mm radiator, customers can add a single regular NF-A12x25 G2 PWM fan to the Sx2-PP set(s) and reduce its running speed to the level of the PPA fan (~1750rpm) through PWM control.

Highly Optimised P/Q Curve for All Applications

The NF-A12x25 G2’s sophisticated aerodynamic design allows for a pressure to airflow (P/Q) curve that is extremely strong in the critical mid-section. This means that the NF-A12x25 G2 is a true jack-of-all-trades with excellent performance in both static pressure demanding and airflow demanding applications.

Excellent on-Application Acoustics

While many fans produce unpleasant, high-pitched noises when installed in typical applications such as on heatsinks or radiators, the NF-A12x25 G2 has been carefully fine-tuned for optimal on-application acoustics. It produces a smooth, pleasant frequency profile and surprisingly low sound pressure levels (SPL) when working against back pressure.

Progressive-Bend Impeller

The NF-A12x25 G2 features a unique Progressive-Bend impeller with Flow Acceleration Channels and winglets. Its nine blades are swept backwards close to the hub and progressively bent forward further out. Working in tandem with the Centrifugal Turbulator hub, this design not only helps to push more air towards the outer blade areas where efficiency is higher but also assures maximum lift and near uniform loading across the entire blade span.

Centrifugal Turbulator Hub

Acting as a turbulator, the new Centrifugal Turbulator hub design improves flow attachment in the hub region. At the same time, it’s centrifugal driving motion pushes air outwards from the hub area where efficiency is low due to the slow rotational speed towards the outer, high-efficiency zones of the blades, thereby increasing overall efficiency by optimising fluid distribution across the impeller area.

Flow Acceleration Channels

The NF-A12x25 G2 impeller features suction side Flow Acceleration Channels. By speeding up the airflow at the crucial outer blade regions, this measure reduces suction side flow separation and thus leads to better efficiency and lower vortex noise.

Winglets

Winglets can help to reduce tip vortices that are caused by the pressure differential between the suction and the pressure side of fan blades but bear the risk of reducing efficiency due to extra fluid displacement in high velocity regions. The NF-A12x25 G2’s small winglets have been carefully fine-tuned to provide consistent efficiency gains working in tandem with its Progressive Bend blade geometry, Flow Acceleration Channels and AAO frame.

Ultra-Tight Tip Clearance

The NF-A12x25 G2 has an extremely tight tip clearance (distance between the blade tips and the inside of the frame) of only 0.5mm. This highly ambitious design helps the NF-A12x25 G2 to work more efficiently against back pressure, such as on heatsinks or radiators, by reducing leak flows through the gap between impeller and frame.

Sterrox® Liquid-Crystal Polymer Compound

The NF-A12x25 G2’s impeller is made from Noctua’s novel Sterrox® liquid-crystal polymer (LCP) compound that features extreme tensile strength, an exceptionally low thermal expansion coefficient and damping characteristics that are ideal for reducing resonance and vibration phenomena in advanced fan-blade designs.

AAO Frame

Noctua's AAO (Advanced Acoustic Optimisation) frames