Featuring advanced aerodynamic design measures such as Flow Acceleration Channels and Noctua’s AAO frame, the NF-A6x25 FLX is a highly optimised, premium quality quiet fan in 60x25mm size. Smooth Commutation Drive technology and Noctua’s reference class SSO2 bearings guarantee superb running smoothness and excellent long-term stability. Topped off with modular cabling, Low-Noise Adaptors and 6 years manufacturer’s warranty, the NF-A6x25 is a premium choice for the highest demands.
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.
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.
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.
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.
Smooth Commutation Drive 2

Smooth Commutation Drive 2

The latest version of Noctua's advanced Smooth Commutation Drive system ensures superb running smoothness by eliminating torque variations and switching noises. This makes the NF-A6x25 remarkably quiet even at very close distances.
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.
3 speed settings for full flexibility

3 speed settings for full flexibility

Providing 3000, 2400 and 1600 rpm speed settings via the supplied Low-Noise and Ultra-Low-Noise Adapters, the NF-A6x25 FLX (Flexibility) can be fine-tuned for superior airflow or maximum quietness.
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 the supplied 3:4 pin adaptor allows the connection of the fan directly to the power supply.
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 FLX
FAN Specification
60x60x25 mm
Blade Geometry
Rotational Speed (+/- 10%)
3000 RPM
Rotational Speed with L.N.A. (+/- 10%)
2400 RPM
Rotational Speed with U.L.N.A. (+/- 10%)
1600 RPM
29,2 m³/h
Airflow with L.N.A.
23,5 m³/h
Airflow with U.L.N.A.
16,7 m³/h
Acoustical Noise
19,3 dB(A)
Acoustical Noise with L.N.A.
14,5 dB(A)
Acoustical Noise with U.L.N.A.
8,2 dB(A)
Static Pressure
2,18 mm H₂O
Static Pressure with L.N.A.
1,41 mm H₂O
Static Pressure with U.L.N.A.
0,61 mm H₂O
Max. Input Power
1,44 W
Max. Input Current
0,12 A
12 V
> 150.000 h
Scope of Delivery
  • Low-Noise Adapter (L.N.A.)
  • Ultra-Low-Noise Adapter (U.L.N.A.)
  • 3:4-Pin Adaptor
  • 30cm Extension Cable
  • 4 Vibration-Compensators
  • 4 Fan Screws
6 years
NF-A6x25 FLX
A-Series fans
17.01.2013 // PC Ekspert

NF-A6x25 FLX Review

Cijene manjih (A4x10/A6x25/A9x14 – 12,90/14,90/16,90€), kao i većih 140mm modela (21,90€) su uglavnom u skladu s dosadašnjom politikom Noctua proizvoda, koja se i dalje bazira na principu – kvaliteta prije svega, uz odgovarajuću cijenu. Nakon svega viđenog, zaista im ne možemo puno zamjeriti na tome, s obzirom na sve prednosti njihovih proizvoda iz nove A-serije za koje imamo gotovo isključivo riječi hvale.
Test verdict: "Noctua nam je ovom prilikom priredila mnoga iznenađenja po pitanju novih proizvoda raznih veličina i namjena. Od minijaturnog 40mm A4x10 modela, preko A6x25 i A9x14, pa sve do 140mm inačica, svaki od testiranih ventilatora odaje onu poznatu Noctua kvalitetu i uglađenost u radu uz visoku funkcionalnost i bogatu dodatnu opremu. Za svakoga ponešto, bi možda bio najslikovitiji opis nove A-serije ventilatora, a što se nas osobno tiče, itekako bismo voljeli vidjeti par 140mm ULN modela i u našem testnom računalu. Za korisnike koji zahtijevaju veliku efikasnost i relativno umjeren nivo buke, tu su naravno A14 FLX i A15 PWM modeli, koji svojom fleksibilnošću, elegantnim radom ali i visokom kvalitetnom izrade itekako zaslužuju našu preporuku." (Domagoj Hodak, PC Ekspert)
22.11.2012 // DragonSteelMods.com

NF-A6x25 FLX Review

Once I got it all installed I powered it on and it didn’t work, at least not at first, the fan apparently comes on when the blu-ray player gets warm enough. (I already knew this actually as I made sure by testing the original fan first) The fan worked perfectly as the original did. The Noctua fan is much quieter than the original fan, which is what you want for something that’s in your home theater. Who wants to hear a fan whirring while they’re watching a movie right? I know I don’t.
Test verdict: "The installation of this type and size of fan will vary on your uses or needs of course, but for any purpose I think it will work just fine. Noctua is known for quality products and their new line of fans certainly keep up with that tradition. My installation was just one option of countless ones I’m sure, but for me it works very well at keeping things cool and being quiet at the same time. Noctua has shown that no matter what your uses, they have the right fan for you." (Kristofer Brozio, DragonSteelMods.com)
20.11.2012 // HWBox.gr

NF-A6x25 FLX Review

O... μεσαίος της παρέας ξύπνησε αναμνήσεις. Έχουν περάσει αρκετά χρόνια από τότε που χρειαζόμασταν να βάζουμε αρκετούς ανεμιστήρες στα τυπικά τσίγκινα μπεζ κουτιά που χρησιμοποιούσαμε για το μηχάνημά μας, και από τις λιγοστές θέσεις που περιελάμβαναν, σίγουρα θα υπήρχε κάποια που ήταν μέγιστο 80mm αλλά μπορούσε να φιλοξενήσει και 60άρηδες, οι οποίοι πέρα από δυσεύρετοι, ήταν και θορυβώδεις. Να όμως που εν έτη 2012 συνεχίζουν και υπάρχουν, και μάλιστα υπό το όνομα της Noctua! Ο ανεμιστήρας διαθέτει μια διαφορετική σχεδίαση, καθώς το πλάτος του έλικα όσο και το συνολικό πλάτος του ανεμιστήρα είναι υψηλού προφίλ και ανέρχεται στα 25mm, παρόμοιο δηλαδή με έναν τυπικό ανεμιστήρα. Με την αρκετά επιτυχημένη (επαν-)είσοδο των desktop cases για mITX form factor, τα οποία έχουν ύψος που μετά δυσκολίας μπορεί να χωρέσει κάποιον 80mm ανεμιστήρα, ίσως και να βρήκατε την -ήσυχη- λύση που αναζητούσατε! Στις τυπικές προδιαγραφές του ανεμιστήρα, μπορεί να παρέχει 50,5 m^3/h στις 2200 RPM(max) και όλα αυτά με ονομαστικό θόρυβο 19,3 dB.
Test verdict: "Δυστυχώς, το τίμημα για κάτι τέτοιους ανεμιστήρες είναι αρκετά υψηλό, αν και είναι δεδομένη η υψηλή ποιότητά τους και η πληθώρα αξεσουάρ με τα οποία συνοδεύονται." (Vasilis Galiouras, HWBox.gr)
14.11.2012 // El Chapuzas Informático

NF-A6x25 FLX Review

Hemos probado los tres ventiladores y gratamente nos ha sorprendido su bajo nivel de ruido generado. El modelo de A4x10 es el único mínimamente más audible, pero por sus altas revoluciones es normal. Los modelos de 40 y 60 mm son perfectos para sistemas embebidos que requieren un ventilador para la extracción de aire, así como para los amantes del modding que deseen refrigerar zonas de su PC de menor superficie. El modelo de 90 mm es ideal para equipos HTPC con disipadores de perfil bajo, que lo verán aún más reducido al cambiar los habituales ventiladores de 25 mm de grosor por este de 14 mm.
Test verdict: "Los ventiladores Noctua Serie-A ofrecen en formato compacto el rendimiento esperado por un ventilador de esta prestigiosa marca: gran flujo de aire a un mínimo nivel sonoro. Su uso está limitado a necesidades concretas, por lo que gran parte de los usuarios no tendrán necesidad de ellos. Sin embargo, los que requieran productos de estas dimensiones agradecerán en gran medida el lanzamiento de estos ventiladores tan eficientes por parte de Noctua." (Iván Martínez, El Chapuzas Informático)
28.10.2012 // PCkoloji.com

NF-A6x25 FLX Review

3-pin girişle beslenen sabit hız fan 3000 devire çıkıyor ama inanılmaz sessiz ve sadece 19.3 dBA gürültü yapıyor. Hava akımı 29.2 m³/h gibi etkileyici bir değer. 92 mm modele göre çok daha ufak olmasına rağmen aynı gürültüyle yüzde 60′ı kadar hava basabiliyor. LNA hız kesici ile hız 2400 devire, gürültü 14.5 dBA’e ve akım 23.5 m³/h değerine iniyor. Bu durumda sesini duymak çok çok zor ama hava akımı çok başarılı.
Test verdict: "ULNA filtre ile hız 1600 devir, gürültü 8.2 dBA ve akım 16.7 m³/h. Akım düşük olsa da sesini duymak için 2 cm mesafeden kulak dayamak gerekiyor! En yüksek devirde 1.44 Watt güç tüketen ve 12V ile beslenen fanın kullanım ömrü en az 150 bin saat. Bu modelde de darbe emici kenar kauçukları var." (Görkem Yildirimy, PCkoloji.com)
22.10.2012 // HD Technology

NF-A6x25 FLX Review

Le ventole Noctua della nuova serie A, sono state veramente all’altezza delle nostre aspettative, qualità impeccabile ed una longevità eccezionale. Gli appassionati potranno utilizzare queste ventole per una durata di oltre 150.000 con una garanzia sul prodotto di ben 6 anni. Come tutte le fan delle varie serie, sono curate minimamente sotto ogni punto di vista.
Test verdict: "Con questa recensione, non possiamo far a meno di consigliarvi queste ventole per chi utilizza un HTPC." (Victor Italiano, HD Technology)
11.10.2012 // Hardware - HDblog

NF-A6x25 FLX Review

Dall’immagine si evince che, anche se siamo davanti a delle ventole molto piccole, la potenzialità che presentano è notevole anche rispetto alla sorella più grande da 92 mm, facendo registrare la stessa temperatura dell’hard disk utilizzando il modello A6x25 e, la ventola più piccola soltanto un grado di differenza rispetto alle sorelle più grandi. Segnaliamo infine la poca rumorosità di tutti e tre i modelli, confermando di fatto le specifiche proposte dall’azienda.
Test verdict: "Come da copione, anche con queste nuove ventole Noctua non ci ha delusi, proponendo prodotti che anche se di piccole dimensioni svolgono bene il proprio lavoro sia per prestazioni che la qualità; tutti e tre i modelli sono ideali per chi cerca prestazioni ottimali per il proprio sistema senza tralasciare la rumorosità." (Michele Bruno, Hardware - HDblog)
08.11.2015 // AndroidPC.es

NF-A6x25 FLX 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)
09.02.2015 // QWERTYmag.it

NF-A6x25 FLX Review

In questa recensione ci siamo realmente resi conto di quanto Noctua sia attenta ai dettagli e alla cura dei propri prodotti anche in delle “semplici” ventole che poi, in questo caso specifico, semplici non sono visto l’elevata cura nella produzione e nelle tecnologie adottate. Ci ha stupito moltissimo il fatto di ritrovare tutte le tecnologie citate nell’introduzione anche nelle ventole di dimensione ridotta come le NF-A4. Siamo decisamente soddisfatti sia dalle prestazioni in termini di efficienza/rumore, sia dal bundle che dai prezzi decisamente in linea con quelli di altri produttori ma assolutamente superiori in termini di caratteristiche e prestazioni. Attribuiamo a tutta la NF-A Series il premio Gold Award per l’innovazione tecnologica e la cura dei particolari che L’azienda ha dimostrato in questa serie di ventole super-efficienti.
Test verdict: "Ventole per ogni tipo di esigenza. Noctua con la serie NF-A ha pensato proprio a tutti e a tutto proponendo prodotti di altissima qualità e tecnologia mantenendo un ottimo rapporto qualità/prezzo. Decisamente apprezzata la cura dei dettagli e del bundle che rendoni queste ventole il TOP DI GAMMA sul mercato." (Davide Torno, QWERTYmag.it)
03.11.2014 // Conseil Config

NF-A6x25 FLX Review

Malgré la taille qui présageait des nuisances sonores horribles comme nous avons tous l'habitude d'entendre venant de ventilateurs comme ceux-ci, et bien il n'en est rien! Le ventilateur qui me faisait le plus peur était le tout petit Ax410, un ventilateur de 4cm qui, tournant à 4500 RPM, me donnait mal aux oreilles avant même de le brancher, mais au final il se révèle être extrêmement silencieux, du très bon pour Noctua qui pourra enfin vous réconcilier avec vos appareils utilisant des ventilateurs de cette taille. Le A6x25 est le plus silencieux du lot, il n'y a aucun bruit parasite audible et il saura se faire discret même au maximum. Le A9x14, qui n'est autre qu'un ventilateur 92 mm au format "low profile" est un modèle qui est très intéressant si vous êtes en manque de place dans vote HTPC (ou tout autre boitier avec peu de place), il a une grande plage d'utilisation et saura se faire très discret, à noter qu'il émet un léger son aigu à plein régime.
Test verdict: "Que dire de cette série un peu spéciale de chez Noctua? Au départ un peu sceptique quant au bruit que génèrent généralement ces types de ventilateurs il faut avoué que j'ai été agréablement surpris. [...] si vous cherchez à remplacer un ventilateur criard (par exemple dans un switch, ou un NAS etc..) par un silencieux vous avez trouvé ce qu'il vous faut!" (Christian Marchini, Conseil Config)

Installation Manual (PDF)

Information Sheet (PDF)

I get a CPU fan error despite the fan is running!

Some mainboards display a CPU fan error when the fan speed falls below a certain threshold, e.g. 900rpm. If you want to run the fan below this speed (e.g. using the supplied U.L.N.A.), please adjust the threshold in the BIOS or disable CPU fan error warning.

Can I disassemble my fan for cleaning?

In order to ensure flawless operation over many years of usage, all Noctua fans come with a premium grade SSO bearing, which is fully sealed to prevent the entering of fine dust particles. Please note that the fan is not designed to be taken apart by the user. Removing the impeller from the frame will break the sealing of the bearing and results in a loss of warranty.

It is thus recommended to clean your fans using a duster, slightly moist tissue or canned air. Please be careful not to use too much force in order to prevent any damage to the fan. Please don’t use a vacuum cleaner as this may apply excessive force to the fan.

Can I paint my Noctua fan in order to change its color?

Since even small variations in the layer of paint can lead to an imbalance of the impeller, resulting in vibrations, higher noise levels, increased stress on the bearing and thus reduced lifespan, we do not recommend painting the fan. Please note that for the reasons stated above, painting the fan will void your warranty.

How can I find out the direction of airflow and sense of rotation?

When looking at the fan so that the circular sticker with the Noctua logo is facing you, the direction of airflow is towards you and the sense of rotation is clockwise:


How should I clean my Noctua fan?

Fans inside computer cases tend to accumulate dust over longer periods of usage. In order to maintain maximum performance, please clean your fans regularly using a duster, slightly moist tissue or canned air. Please be careful not to use too much force in order to prevent any damage to the fan. Please do not use a vacuum cleaner as this may apply excessive force to the fan and do not put the fan under running water as water residues inside the motor may lead to short circuits.
In order to ensure flawless operation over many years of usage, Noctua’s premium grade SSO bearings are fully sealed to prevent the entering of fine dust particles. Please note that the fan is not designed to be taken apart by the user. Removing the impeller from the frame will break the sealing of the bearing and results in a loss of warranty.

My Noctua 3-pin fan starts to spin when the PC boots but then stops, what is wrong?

Many mainboards are able to automatically regulate the fan speed of 3-pin fan via voltage based measures. However, due to limitations of this method it may occur that the mainboard reduces the voltage so much that the fan stops. To resolve the issue, you can:

  1. Choose a higher fan speed profile in the BIOS (e.g. „normal“ instead of „silent“, etc.) or deactivate automatic fan speed control and use a Low-Noise Adaptor instead.
  2. Use the mainboard‘s fan speed control software or 3rd party tools like Speedfan to regulate the fan speed. Unlike BIOS based fan speed control, the supplied software usually checks whether the fan has stopped and increases voltage accordingly or at least offer more options to set up the fan properly.

What pin configuration do Noctua fans use?

All Noctua fans feature the standard pin-configurations set out in the Intel and AMD specifications. These standard pin-configurations are used on most mainboards and fan controllers today:


You specify airflow in m³/h, how can I convert to CFM?

In accordance to the International System of Units (SI system), Noctua specifies volumetric flow rate (airflow) using the SI unit of cubic metres per hour (m³/h). The SI unit can easily be converted to cubic feet per minute (CFM): One m³/h is ~0.589 CFM and one CFM is ~1.699 m³/h. For convenient conversion, online tools such as www.convertunits.com can be used.

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