NF-A12x25 G2 PWM Sx2-PP

Next-gen 120mm fan set

Next-gen 12cm design

For unprecedented quiet cooling performance

State-of-the-art engineering

Progressive Bend impeller, Sterrox® LCP material & ultra tight tip clearance

Dual fan set

For push-pull and side-by-side usage

Variant:

PWM LS-PWM PWM Sx2-PP

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.

techPowerUp.com•VSG

“Incredible performance across the board, quieter than the competition.”

PC Gamer•Jacob Ridley

“The best overall: The NF-A12x25 G2 excels in testing. At 1200, 800, and 450 RPM, it outperformed all other fans we tested. There are faster fans, but few others can compete on as many metrics as this one.”

FunkyKit.com•Bartosz Waluk

“The new fans are definitely the best you can buy in stores. They’re not cheap, but if you plan on building a PC and forget about the fans for long years, then Noctua is the answer. I won’t hide that we have reviewed and used Noctua fans for over ten ...”

HWCooling.net•Ľubomír Samák

“The Noctua NF-A12x25 G2 (PWM) is the most efficient fan we’ve ever tested. It clearly outperforms its predecessor (NF-A12x25 “G1”), as well as the Phanteks T30 and all competing 120 mm fans in the extensive database we’ve built so far. The NF-A12x25 ...”

PC Games Hardware•Jan Hauck

“Noctuas neuer NF-A12x25 G2 kann sich im Test als neue Evolutionsstufe beweisen. Wie das größere 140-mm-Modell macht auch der kleine Bruder einen deutlichen Leistungssprung und überzeugt auf ganzer Linie. Lediglich die geringe maximale Drehzahl schrän...”

Hardwareluxx.de•Philipp Moosdorf

“Noctua hat beim NF-A12x25 G2 wirksame Optimierungsmaßnahmen umgesetzt und so tatsächlich einen Fortschritt gegenüber dem Vorgänger erzielt. Wer einen vielseitig nutzbaren Premiumlüfter mit überschaubarer Maximaldrehzahl sucht, ist entsprechend gut be...”

HardwareAsylum.com•Dennis Garcia

“This is a second-generation release of the NF-A12x25 that we reviewed back in 2018 and is by far one of the best fans I have ever used. The G2 takes things to the next level with only a few minor tweaks to the design.”

QWERTY Articles•Justin Vendette

“A meticulously engineered fan that delivers top-tier cooling with whisper-quiet operation, the NF-A12x25 G2 sets a new gold standard for 120 mm PC fans.”

CowcotLand.com•Sébastien Vandeborre

“Après une longue attente, Noctua frappe fort sur le segment haut de gamme. Avec son NF-A12x25 G2, la marque propose un ventilateur bon à tout faire qui fonctionne particulièrement bien, et ce malgré une vitesse de rotation faible sur le papier si on ...”

Key features

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.

Diagram of Noctua's SSO2 fan bearing. Blue arrows show magnetic self-stabilization, green dashed lines indicate magnetic field.

SSO2 bearing

The NF-A12x25 G2 features the further optimised second generation of Noctua's renowned, time-tested SSO bearing. With SSO2, the rear magnet is placed closer to the axis to provide even better stabilisation, precision and durability.

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.

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.

Further resources

Want to know more on this topic? Explore relevant articles and resources.

All articles

NF-A12x25 G2: further refined performance in all applications

tech

The NF-A12x25 G2 represents another step up in performance, surpassing its renowned predecessor in all typical use cases.

G2 fan series aerodynamic innovations

tech

Building on the technological innovations of the NF-A12x25, the G2 models represent a further refined, second-generation implementation of this design approach.

etaPERF™ motor

tech

Smarter, quieter, more efficient: The etaPERF™ motor maximizes power with minimal energy loss, delivering superior performance and near-silent operation.

SupraTorque™

tech

SupraTorque™ ensures Noctua fans don’t lose speed under pressure, improving cooling efficiency—especially in high-resistance setups.

Overlapping frequencies of 10 Hz and 9 Hz, shifting in and out of phase

Fan speed offset explained

tech

When two fans are running together at almost the same speed, their acoustic interaction can lead to undesirable harmonic phenomena, known as beat frequencies.