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Featuring advanced aerodynamic design measures such as Flow Acceleration Channels and Noctua’s AAO frame, the NF-A6x25 is a highly optimised, premium quality quiet fan in 60x25mm size. The PWM version sports Noctua’s custom designed NE-FD1 IC for fully automatic speed control via 4-pin fan headers and comes with a Low-Noise-Adaptor to reduce the maximum speed during PWM control from 3000 to 2300rpm. Its superb running smoothness, SSO2 bearing and Noctua’s trusted premium quality make it an elite choice for the highest demands.
Details
Flow Acceleration Channels

Flow Acceleration Channels

The NF-A6x25 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.
Reduced Motor Hub Size

Reduced Motor Hub Size

Thanks to its streamlined, compact motor design, the NF-A6x25's motor hub is smaller than with conventional 6cm fans. This allows for more blade surface area and thus contributes to the NF-A6x25's superior airflow and pressure performance.
AAO Frame

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.
Inner Surface Microstructures

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.
Stepped Inlet Design

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.
Integrated Anti-Vibration Pads

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 mounting systems and fan clips used on heatsinks.
SSO2 Bearing

SSO2 Bearing

The NF-A6x25 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.
Custom-designed PWM IC with SCD

Custom-designed PWM IC with SCD

Supporting fully automatic PWM speed control, the NF-A6x25 PWM uses Noctua's custom-designed NE-FD1 PWM IC that integrates Smooth Commutation Drive (SCD) technology. By providing smoother torque impulses, SCD suppresses PWM switching noises and thus makes the fan quieter at low speeds.
Low-Noise Adaptor

Low-Noise Adaptor

The NF-A6x25 PWM is supplied with a (L.N.A.) that reduces the maximum fan speed from 3000 to 2300rpm. The L.N.A. can be used either to run the fan at a fixed speed of 2300rpm or to cap the maximum speed when using automatic PWM control.
Extensive cabling options

Extensive cabling options

The fan's short 20cm primary cable minimises cable clutter in typical applications while the supplied 30cm extension provides extended reach when necessary. Both cables are fully sleeved and a 4-pin y-cable allows the connection of a second NF-A6x25 PWM fan to the same PWM fan header for automatic control.
6-year manufacturer’s warranty

6-year manufacturer’s warranty

Noctua fans are renowned for their impeccable quality and outstanding longevity. Like all Noctua fans, the NF-A6x25 features an MTBF of more than 150.000 hours rating and comes with a full 6-year manufacturer’s warranty.
NF-A6x25 PWM
FAN Specification
Size
60x60x25 mm
Mounting hole spacing
50x50 mm
Connector
4-Pin PWM
Bearing
Blade Geometry
Rotational Speed (+/- 10%)
3000 RPM
Rotational Speed with L.N.A. (+/- 10%)
2300 RPM
Min. Rotational Speed (PWM, +/-20%)
550 RPM
Acoustical Noise
19,3 dB(A)
Acoustical Noise with L.N.A.
13,7 dB(A)
Static Pressure
2,18 mm H₂O
Static Pressure with L.N.A.
1,29 mm H₂O
Max. Input Power
0,96 W
Max. Input Current
0,08 A
Voltage
12 V
MTTF
> 150.000 h
Scope of Delivery
  • Low-Noise Adaptor (L.N.A.)
  • 4-Pin Y-Cable
  • 30cm Extension Cable
  • 4 Vibration-Compensators
  • 4 Fan Screws
Warranty
6 years
NF-A6x25 PWM
NF-A6x25 PWM Video
08.11.2015 // AndroidPC.es
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NF-A6x25 PWM Review

Después de probar los modelos NF-A6x25 PWM, NF-A6x25 FLX, NF-A4x10 FLX y NF-A4x10 5V nos dan ganas de dejar un ventilador en nuestras placas pasivas, pero preferimos no hacerlo, como ya sabéis nos gustan los sistemas pasivos. Ciertamente es estos productos pueden ofrecen una mejora térmica en nuestros dispositivos si vamos a exprimirlos y además no nos molestan con ruidos. Si tenemos algún modelo pasivo con problemas térmicos añadirle un pequeño ventilador bien dimensionado siempre es una solución, sobretodo si tienen la calidad de estos modelos.
Test verdict: "Los recomendamos sin ninguna duda para quien quiera mejorar el rendimiento de su miniPC o AndroidPC con problemas térmicos." (Joaquin Prida Trujillo, AndroidPC.es)
15.04.2015 // ByTheWay.gr
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NF-A6x25 PWM Review

Κλείνοντας,οι επιδόσεις του νέου NF-A6x25 PWM είναι εξαιρετικές. Καταφέρνει να έχει σπουδαίες επιδόσεις και εξαιρετικά επίπεδα θορύβου με τον low noise adapter που προσφέρει η εταιρία. Set it and forget it προσέγγιση και μπορούμε να εγγυηθούμε το "forget it" κομμάτι. Η επιμονή στην λεπτομέρεια της Noctua είναι προφανής. Μερικές από τις αναφερόμενες τεχνολογίες θυμίζουν μελέτες αεροδυναμιστών παρά κατασκευαστών computer parts και η παρεχόμενη εγγύηση των 6 ετών είναι χωρίς προηγούμενο σε μια αγορά που η 3ετής πλέον θεωρείται πολυτέλεια. Σκεφτείτε το, το 2020 οι ανεμιστήρες σας θα είναι ακόμα εντός εγγύησης και μάλιστα από μια εταιρία που συνηθίζει να την τιμά, χωρίς αστείες δικαιολογίες.
Test verdict: "Η Noctua δείχνει ότι δεν αγχώνεται να διώξει το premium χαρακτήρα της ούτε από την τιμολογιακή της πολιτική, και ειλικρινά δεν περιμέναμε κάτι διαφορετικό εκεί. Όμως, αυτό που έχουμε να παρατηρήσουμε είναι η κορυφαία ποιότητα κατασκευής σε συνδυασμό με τον εξαιρετικό σχεδιασμό που επιφέρουν καλύτερες επιδόσεις, ενώ ταυτόχρονα μπορούν και προσφέρουν ήσυχη και απρόσκοπτη λειτουργία ακόμα και σε πολύωρη χρήση." (Nasioulis Evangelos, ByTheWay.gr)

Installation Manual (PDF)

Information Sheet (PDF)

I'm experiencing fan speed issues with my motherboard from Supermicro, what can I do?

The BIOS of many motherboard models from Supermicro expects a certain minimum fan speed (usually 700rpm), which is higher than the minimum fan speed that can be achieved with Noctua's PWM fan models. The BIOS may interpret the low minimum RPM of Noctua fans as a fan error and thus try to run the fan at 100% for a short period before going back to automatic control.. This can result in oscillating fan speeds and fan speed warnings in the BIOS or the fan management console.

Unfortunately there is usually no option to set a lower minimum value that would suit the low minimum speed of Noctua PWM fans.The issue can thus only be resolved by either disabling automatic fan speed control in BIOS, which will cause the fans to run at a constant speed, or by requesting a modified BIOS file from Supermicro, which takes the minimum fan speed of Noctua fans into account (charges might apply).

Can I use Low-Noise Adaptors with y-cables / multiple fans?

Yes, Low-Noise Adaptors (L.N.A.s) can be used with y-cables, but please make sure to use one L.N.A. per fan and to place the L.N.A.s between the y-cable and the fans as shown below. Never use one L.N.A. for two (or more fans) by placing it between the mainboard and the y-cable!

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Can I run 4-pin PWM fans on 3-pin fan headers?

PWM fans come with a 4-pin connectors for fully automatic speed control via your mainboard’s 4-pin PWM fan headers. Please note that 4-pin fans can also be connected to your mainboard’s 3-pin fan headers though. When connected to 3-pin fan headers, the fan will run at full speed (unless the mainboard supports voltage based speed control).

How can I check if my 4-pin fan header supports PWM?

Some mainboards feature 4-pin fan headers that actually don‘t use a PWM signal on Pin 4 to control the fan speed but rather reduce the voltage on Pin 2 (like a standard 3-pin fan header). As the fan speed at minimum voltage is usually higher than the speed at 20% PWM duty cycle, the fan can not reach as low minimum speeds under voltage control as under PWM control. Please refer to your mainboard manual to check whether or not your mainboard has 4-pin fan headers that control the fan speed by reducing voltage on Pin 2 rather than by changing the PWM duty cycle on Pin 4:

4 pin fan header types

Note that mainboard manufacturers use different terms to indicate that Pin 4 is not being used for PWM control (e.g. “+5V”, “VCC” or “NC”), but if one of these terms is used, you can be sure that the fan header does not support PWM. If Pin 4 is described as “Speed Control” or “PWM” or the like, you can be sure that the fan header supports PWM.

Unfortunately, the description of Pin 2 is not always a clear indication as some manufacturers use terms such as “Fan PWR” or “Power” for both types of fan headers. However, if Pin 2 is described as “Speed Control”, you can also be sure that the fan header does not support PWM based speed control. If Pin 2 is described as “+12V”, this is a clear indication that the fan header supports PWM.

Please also note that in some cases, the descriptions of the pin layouts in the mainboard manuals may not be correct and some models actually allow you to switch the fan headers from voltage control mode to PWM control mode in the BIOS even though the pin descriptions do not indicate PWM support. We thus recommend to look for these options in the BIOS before taking other measures. In case of doubt, please contact your mainboard manufacturer.


If your mainboard features other 4-pin fan headers that use PWM for speed control, you can run multiple fans from these headers using Y-split cables. Make sure not to exceed the specified maximum power draw of the fan headers (usually 10-12W) though.

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