Noctua NF-A14x25R G2 140mm PWM SX2-PP Fan 2 Pack

The Noctua NF-A14x25R G2 PWM SX2-PP Fan features advanced aerodynamic design elements enhancing its efficiency and cooling capabilities, is made from Sterrox liquid-crystal polymer (LCP) compound making the fan both durable and effective in maintaining low noise levels even under high pressure, includes a Low-Noise Adaptor to reduce maximum speed from 1500 to 1250 RPM and is ideal for push-pull configurations on heatsinks like the NH-D15(S) or NH-U14S.

Features

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NF-A14x25r G2 PWM Sx2-PP

The NF-A14x25r G2 PWM Sx2-PP is a set of two NF-A14x25r G2 PWM round-frame 140mm fans for push-pull operation on heatsinks such as the NH-D15(S) or NH-U14S. When two fans operate in a push-pull configuration running at almost the same, constant speed, 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-A14x25r G2 PWM fans contained in the Sx2-PP set are slightly offset in speed (+/- ~25rpm) 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 leverages extra torque headroom to keep the exact desired speed even when working against significant flow resistance such as on heatsinks. With one fan running ~25rpm slower (PPA) and one ~25rpm 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.

*sample image - only NF-A14x25r G2 PWM included.

Push-Pull Set

Bundling two NF-A14x25r G2 PWM fans that are speed-offset by +/- 25rpm in order to avoid undesired acoustic interaction phenomena, the Sx2-PP set is the ideal choice for push-pull configurations on 140mm class coolers such as the NH-D15(S) or NH-U14S.

Next-Generation Performance

Noctua’s NF-A15 is renowned as being among the best round-frame 140mm fans on the market and has received more than 100 awards and recommendations from the international press. With its further improved efficiency and novel, state-of-the-art engineering, the NF-A14x25r G2 represents another step up in performance and manufacturing.

Highly Optimised P/Q Curve for All Applications

The NF-A14x25 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-A14x25 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-A14x25 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-A14x25 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-A14x25 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-A14x25 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-A14x25 G2 has a record tight tip clearance (distance between the blade tips and the inside of the frame) of only 0.7mm. This highly ambitious design sets a new benchmark for 140mm fans and helps the NF-A14x25 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-A14x25 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 feature integrated anti-vibration pads as well as Noctua's proprietary Stepped Inlet Design and Inner Surface Microstructures, both of which further refine the fan's performance/noise efficiency.

Stepped Inlet Design

Noctua's Stepped Inlet Design adds turbulence to the influx in order to facilitate the transition from laminar flow to turbulent flow, which reduces tonal intake noise, improves flow attachment and increases suction capacity, especially in space-restricted environments.

Inner Surface Microstructures

With the tips of the fan blades ploughing through the boundary layer created by the Inner Surface Microstructures, flow separation from the suction side of the blades is significantly suppressed, which results in reduced blade passing noise and improved airflow and pressure efficiency.

Integrated Anti-Vibration Pads

Integrated anti-vibration pads made from extra-soft silicone minimise the transmission of minute vibrations while maintaining full compatibility with all standard screws and most other mounting mechanisms.

SSO2 Bearing

The NF-A14x25 G2 features the further optimised second generation of Noctua's renowned, time-tested SSO2 bearing. With SSO2, the rear magnet is placed closer to the axis to provide even better stabilisation, precision and durability.

Metal Bearing Shell

In order to guarantee the highest possible degree of manufacturing precision, minimum tolerance and excellent long-term stability, the NF-A14x25 G2 sports a CNC milled bearing shell made entirely from brass.

etaPERF™ Motor with NE-FD6 PWM IC

Noctua’s new etaPERF™ moto