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.
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.
Centrifugal Turbulator hub
Acting as a turbulator, the new Centrifugal Turbulator hub design improves flow attachment in the hub region. At the same time, its 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.
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.
Scope of delivery
- NF-A12x25 G2 PWM PPA
- NF-A12x25 G2 PWM PPB
- 2x NA-RC7 Low-Noise Adaptor (L.N.A.)
- NA-YC1 4-pin PWM splitter cable
- 2x NA-EC1 30cm extension cable
- 8x NA-AV2 anti-vibration mounts
- 2x NA-AVG1 anti-vibration gasket for water cooling radiators
- Fan screws
Highly optimised P/Q curve for all applications
The NF-A12x25 G2’s sophisticated aerodynamic design allows for a pressure to airflow 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 static pressure demanding & airflow demanding applications.
 NF-A12x25 G2 PWM |  NF-A12x25 G2 LS-PWM |  NF-A12x25 G2 PWM Sx2-PP | |
|---|---|---|---|
| Customer Reviews | — | — | — |
| Price | — | — | — |
| Connector | 4-pin PWM | 4-pin PWM | 4-pin PWM |
| Voltage | 12 V | 12 V | 12 V |
| RPM | 1800 RPM | 1100 RPM | 1800 RPM |
| RPM with L.N.A. | 1500 RPM | 850 RPM | 1500 RPM |
| Acoustical Noise | 22.5 dB(A) | 11.8 dB(A) | 22.5 dB(A) |
| Acoustical Noise with L.N.A. | 18.1 dB(A) | 7.8 dB(A) | 18.1 dB(A) |
| Size | 120x120x25 | 120x120x25 | 120x120x25 |
| Colour | Brown & Beige | Brown & Beige | Brown & Beige |
| Quantity | x1 | x1 | x2 |
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.
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.
Centrifugal Turbulator hub
Acting as a turbulator, the new Centrifugal Turbulator hub design improves flow attachment in the hub region. At the same time, its 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.
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.
Scope of delivery
- NF-A12x25 G2 PWM PPA
- NF-A12x25 G2 PWM PPB
- 2x NA-RC7 Low-Noise Adaptor (L.N.A.)
- NA-YC1 4-pin PWM splitter cable
- 2x NA-EC1 30cm extension cable
- 8x NA-AV2 anti-vibration mounts
- 2x NA-AVG1 anti-vibration gasket for water cooling radiators
- Fan screws
Highly optimised P/Q curve for all applications
The NF-A12x25 G2’s sophisticated aerodynamic design allows for a pressure to airflow 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 static pressure demanding & airflow demanding applications.
NF-A12x25 G2 PWM | NF-A12x25 G2 LS-PWM | NF-A12x25 G2 PWM Sx2-PP | |
|---|---|---|---|
| Customer Reviews | — | — | — |
| Price | — | — | — |
| Connector | 4-pin PWM | 4-pin PWM | 4-pin PWM |
| Voltage | 12 V | 12 V | 12 V |
| RPM | 1800 RPM | 1100 RPM | 1800 RPM |
| RPM with L.N.A. | 1500 RPM | 850 RPM | 1500 RPM |
| Acoustical Noise | 22.5 dB(A) | 11.8 dB(A) | 22.5 dB(A) |
| Acoustical Noise with L.N.A. | 18.1 dB(A) | 7.8 dB(A) | 18.1 dB(A) |
| Size | 120x120x25 | 120x120x25 | 120x120x25 |
| Colour | Brown & Beige | Brown & Beige | Brown & Beige |
| Quantity | x1 | x1 | x2 |