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Featuring advanced aerodynamic design measures such as Flow Acceleration Channels and an AAO frame, the NF-A4x20 5V PWM is a PWM enabled 5V variant of Noctua’s highly optimised, premium quality quiet 40x20mm fan. The custom designed NE-FD3 PWM IC that integrates 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, the OmniJoin™ Adaptor Set and 6 years manufacturer’s warranty, the NF-A4x20 5V PWM is a premium choice for demanding 5V applications that require PWM control.

Being a 5V fan, the NF-A4x20 5V PWM cannot be run at 12V and will be damaged when used with typical 12V power sources such as PC motherboard fan headers.
Details
40x20mm size

40x20mm size

Compared to Noctua’s award-winning NF-A4x10, the NF-A4x20 is twice as thick, which allows for increased static pressure performance and makes the NF-A4x20 ideal for demanding applications with high flow resistance.
5V PWM version

5V PWM version

Many devices such as network or storage solutions use 5 volt 40mm fans with PWM speed control. With the same operating voltage, PWM support and the included OmniJoin™ adaptor set that makes it compatible with proprietary fan headers, the NF-A4x20 5V PWM is ideal for replacing noisy or broken 5V 40mm fans with PWM.
Polarity protection

Polarity protection

As many devices using 5V fans feature proprietary connectors, and documentation of the pin alignment may not be available, the fan features an integrated diode for polarity protection. This way, you're on the safe side if you accidentally connect it with reverse polarity.
Flow Acceleration Channels

Flow Acceleration Channels

The NF-A4x20 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.
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.
Custom-designed PWM IC with SCD

Custom-designed PWM IC with SCD

Supporting fully automatic PWM speed control, the fan uses Noctua's custom-designed NE-FD3 5V 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.
OmniJoin™ adaptor set

OmniJoin™ adaptor set

Many devices featuring 40mm fans use proprietary fan headers, so the NF-A4x20 comes with Noctua's OmniJoin™ adaptor set. Just cut the original fan's cable, fix it to the adaptor using the supplied 3M Scotchlok™ connectors and you can plug the NF-A4x20 to proprietary fan headers!
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 fan to the same PWM fan header for automatic control.
SSO2 bearing

SSO2 bearing

The NF-A4x20 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.
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-A4x20 features an MTTF of more than 150.000 hours rating and comes with a full 6-year manufacturer’s warranty.
NF-A4x20 5V PWM
General
Notes and warnings
Being a 5V fan, the NF-A4x20 5V PWM cannot be run at 12V and will be damaged when used with typical 12V power sources such as PC motherboard fan headers.
FAN Specification
Size
40x40x20 mm
Mounting hole spacing
32x32 mm
Connector
4-pin PWM
Bearing
Blade Geometry
Rotational Speed (+/- 10%)
5000 RPM
Min. Rotational Speed (PWM, +/-20%)
1100 RPM
Acoustical Noise
14,9 dB(A)
Static Pressure
2,26 mm H₂O
Max. Input Power
0,5 W
Max. Input Current
0,1 A
Voltage
5 V
MTTF
> 150.000 h
Scope of delivery
  • 4-pin y-cable
  • 30cm extension cable
  • OmniJoin™ adaptor set
  • NA-AV3 anti-vibration mounts
  • Fan screws
Warranty
6 years
NF-A4x20 5V PWM
27.09.2017 // El Chapuzas Informático
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NF-A4x20 5V PWM Review

Noctua ha lanzado una nueva colección de productos de gama alta para el apartado de refrigeración que, como siempre, dejan a la marca en excelente lugar. Por un lado, tenemos los ventiladores Noctua NF-A12x15, una excelente alternativa para disipadores slim o chasis compactos donde no tengan cabida los tradicionales de 25 mm de grosor. Los NF-A20 son una opción para chasis que permitan los modelos de 200 mm, aunque no ofrecen una gran mejora frente a modelos de 120 mm. Mientras, los NF-A4x20 son un sustituto ideal para dispositivos ultracompactos, ya sea por reparación o para mejorar su sonoridad. Por si fuera poco, todos ellos ofrecen nada menos que 6 años de garantía, por lo que tenemos ventiladores para rato. Además, Noctua siempre busca suplir todas las necesidades de sus clientes y para ello lanza algunos accesorios como los que hemos visto, los se unen a un inmenso portafolio que podemos consultar aquí.
Test verdict: "Como no podía ser de otra forma, desde del El Chapuzas Informático le otorgamos el Galardón de Platino a los ventiladores Noctua NF-A12x15, NF-A4x20 y NF-A20 y los nuevos accesorios, productos todos ellos de la más alta calidad. En lo que respecta al precio, en el momento de la redacción no están listados en nuestro país." (Iván Martínez, El Chapuzas Informático)
12.07.2017 // FunkyKit.com
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NF-A4x20 5V PWM Review

We have no doubt about the top quality of Noctua products. Each one of them is well designed. Even the package is exceptional. Most manufacturers are missing these little things that count while Noctua provides package with everything you may need for installation. Long years of designing and engeneering gave great results. Where you could think there can’t be done much more, Noctua proved that even the best products can be improved. New A series fans are the best in their class and it’s hard to find anything similar on the market. Even though new fans are considered as “slim”, they provide top air pressure while keeping low level of generated noise. Perfect balance for all who expect the best from their fans.
Test verdict: "We are recommending all new Noctua products without any hesitation!" (Bartosz Waluk, FunkyKit.com)
10.07.2017 // PC Ekspert
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NF-A4x20 5V PWM Review

Veliki NF-A20 i u PWM i U FLX verziji košta oko 33 € što je korektna cijena za veličinu ventilatora, svu opremu koju donosi i na kraju krajeva vrlo dobre performanse uz ne previsoku buku. Kvaliteta izrade je visoka, materijali odlični a tehnologije jamče dugovječnost – kao i šest godišnje jamstvo uostalom. NF-A12x15 su po cijeni od 24 € pogodni za ugradnju u skučenija HTPC kućišta i na manje hladnjake, a obavezno ih se treba malo usporiti jer su na visokim okretajima čujniji. “Propuh” koji stvaraju je vrlo dobar i na nižim okretajima. A4x20 je u svim verzijama oko 20 €. Visoka je to cijena za 40-milimetarske ventilatore, no zbog kvalitete izrade, jamstva i ponajprije velike kompatibilnosti i mogućnosti prilagodbe isplati se platiti i tako visoki iznos. Ventilatori jesu bučniji pri visokim okretajima, no za kakav komad mrežne opreme koji je u ormaru to i nije bitno, a koncentrirana je zračna struja visoka i moćna. NA-SAV3 i SAV4 su po 11.50 € za što kupac dobiva kvalitetu, kompatibilnost s velikim brojem ventilatora i 16 komada nosača za po četiri ventilatora. NA-FC1 je svestran i kvalitetan kontroler za do tri ventilatora koji je moguće napajati direktno iz SATA Power konektora, pa može kontrolirati i jače ventilatore, no nije jeftin – 15 €. I za kraj, NA-SAC5 adapter koji može biti iznimno koristan za jače ventilatore koji se direktno napajaju iz SATA Power konektora i tako ne opterećuju ploču. Negativna je jedino cijena od oko 8 €.
Test verdict: "Noctua koristi svoju veliku ekspertizu u izradi sve boljih ventilatora iz godine u godinu. Novosti za ovu su tri varijante koje smo u ovom članku pokazali i svaka je od njih posebna, a to uključuje i sve izvedenice pojedinih ventilatora. [...] Svi Noctuini proizvodi su kao uvijek korisni i zaslužuju visoke preporuke, a jedino što ima zapravo možemo zamjeriti je nešto viša cijena za naše hrvatske (prazne) džepove." (Krešimir Matanović, PC Ekspert)
15.05.2018 // HardwareSfera.com
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NF-A4x20 5V PWM Review

El ofrecer un buen airflow es algo muy importante y los sistemas NAS y router, suelen flojear en la refrigeración, por eso es muy importante contar con un buen ventilador. La refrigeración de estos componentes normalmente es muy mala y por eso, se requiere mejorar con ventiladores de alta eficiencia y que ofrezca un gran flujo de aire. Sobre todo estos componentes suelen sufrir en verano, que es cuando se necesita más potencia y un gran flujo de aire. Los ventiladores Noctua NF-A4x20, en sus cuatro versiones, son de tan solo 40mm, pensando no solo en sistemas compactos de reducidas dimensiones, sino también en los NAS y los routers, los cuales suelen implementar ventiladores de mala calidad, muy ruidosos y que suelen durar poco tiempo.
Test verdict: "Estos ventiladores se caracterizan por ser de excelente calidad, como no puede ser de otra manera al ser de Noctua y ofrecen un gran flujo de aire, todo lo que se puede pedir en un ventilador." (Roberto Solé, HardwareSfera.com)
20.03.2018 // EnosTech.com
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NF-A4x20 5V PWM Review

Jumping right into things and as you would expect from Noctua, the performance of these products is second to none. Given their respective sizes, all of these fans create a decent amount of airflow when tested in an open world environment, i.e. not in a case but just on a table. As mentioned I have actually used the NF-A4x20’s on a 3D printer in the past and was a great upgrade from the cheap fans that it had originally come with. While some may criticize the colour scheme, I don’t recall hearing very many people talk ill of the performance of any Noctua product. These fans all offer a great amount of airflow, again, for their respective sizes and remain as quiet as possible when doing so. The massive NF-A20’s are for those who need the most airflow possible but do make sure your case or where ever you are using them can cater to their 20cm sizes. The A4x20’s and A12x15’s are for when space is crucial and you need the most from your fans. The small 20mm and their unique size can come in handy for a number of scenarios. The added airflow to say the intake vents on a lot of the newer PC gaming cases is sure to help keep your components as cool as can be. The A12x15 are slimline and will surely come in handy for those looking to go with a push/pull configuration on any radiators for CPU and GPU cooling. Too many times have I seen a case where you can’t install a push/pull configuration due to space restrictions, well no more! Noctua’s A12x15 are sure to help you overcome this issue with ease. All of these fans in their own rights are equally useful and offer the same great performance we have come to know and love from Noctua. As far as the accessories go, they all perform as good as one could hope for. My Favourite was probably the fan controller as it allowed me to control my 2 front intake fans and 1 exhaust fan with ease. During the day I like them silent, but when the headphones come out and the game comes on, it’s time to turn the fans up a bit and this was done easily and quickly. The Anti-vibration mounts are nice as well. Not only do they reduce noise from vibrations, they allow you to install and remove your fans with ease which is always a plus when it comes time to clean them. Lastly, the 4-pin PWM to SATA power cable is a great addition to any build as it will allow you to connect a fan to any extra SATA power cables you have coming from your power supply. Those with motherboards that don’t have a lot of fan headers and are not keen on using a controller will find these very useful.
Test verdict: "If you want the best of the best and you want it to last you for as long as you’ll need, then Noctua has the answer for you. These products on review here today are well worth their individual price tags and you shouldn’t be put off paying a bit extra for them considering everything they have to offer." (Ben Enos, EnosTech.com)
02.01.2018 // PureOverclock.com
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NF-A4x20 5V PWM Review

Another issue that I ran into is the fact that these fans are so incredibly quiet that I was not able to pick them up with my dB meter. The ambient noise in my condo is above that of the fans, and the only one I can audibly hear over anything else any more than a foot away is the 120 mm fan. At 70% speed (thanks again for the awesome tool, Noctua!), I was only able to hear it at the same distance as the other fans. It becomes audible above 70%, but not intrusively. I have an absolutely maddening obsession when it comes to rig silence, so for me to say this, it tells you something. Even the 40 mm fans did me very proud indeed. I was able to hear them a very small amount, but given that they are spinning at 5000 RPM (I may or may not have tried to stick my finger in to slow it down…), it blew me away with its noise level. Simply phenomenal acoustic levels.
Test verdict: "If you can afford the premium price that comes attached with Noctua products, and you don’t mind their browny-beige color scheme, then they are absolutely one of the best fan makers in the world. I honestly forgot how quiet and premium their fans were until I got my hands on the care package that they sent over." (Brendan van Varik, PureOverclock.com)
18.09.2017 // PCElite.pl
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NF-A4x20 5V PWM Review

Ceny za każdy produkt tej firmy są wysokie jednak idzie za tymi cenami jakość wykonania, przemyślana konstrukcja, solidność. Te cechy maja odzwierciedlenie wszędzie, w każdym detalu, nawet w szczegółach związanych z opakowaniem, ze sposobem zaciśnięcia termokurczek. Jedynie do czego mogę się przyczepić to kolorystyka (jedni chwalą jak ja, drudzy ganią) oraz cena.
Test verdict: "Długo myślałem nad podsumowaniem jednak opiszę to krótko – Noctua to Noctua. Dobrze wydane pieniądze." (Arkadiusz Byś, PCElite.pl)
11.09.2017 // Tecnogeekies.com
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NF-A4x20 5V PWM Review

Hoy hemos presenciado como Noctua lo ha vuelto a hacer, las prestaciones de sus nuevos productos continúan siendo la referencia que siempre han sido, pero hay otras cosas que también van a continuar. Frente a las grandes prestaciones tradicionales de Noctua hay otro aspecto que también se mantiene, este nivel de calidad no es barato, desde los 30€ que cuesta el ventilador de 200mm, el NF-A20. El adaptador SATA por 8€, el controlador por 20€ o los sorprendentes 15€ que cuesta el pequeño ventilador de 40mm, pasando por los más razonables 20€ por el ventilador más tradicional de 120mm. No obstante hemos de hacer hincapié en algo que solemos decir en Tecnogeekies bastante a menudo, aunque 20€ pueden parecer muchos, especialmente solo por un ventilador, su calidad y su durabilidad nos hacen recomendar esta marca siempre que vuestro presupuesto os lo permita.
Test verdict: "La calidad tiene un precio, pero en casos como el de Noctua merece la pena." (Ignacio Merino, Tecnogeekies.com)
30.08.2017 // Conseil Config
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NF-A4x20 5V PWM Review

En ce qui concerne le niveau sonore la marque a bien travaillé, les NF-A4 se démarquent de ce que l'on trouve habituellement avec une discrétion très apréciable, les NF-A12 quant à eux sont très silencieux au minimum mais plutôt bruyant une fois alimentés en 12V, rien de bien grave cela dit vu les adaptateurs livrés. Les plus gros NF-A20 sont également silencieux que ce soit au minimum ou au maximum. Proposés à un tarif allant de 7.90€ pour les NF-A4 à 29.90€ pour les NF-A20 en passant par 19.90€ pour les NF-A12x15 ils sont encore une fois réservés à ceux qui ne se satisfont que de produits haut de gamme, ils ne seront clairement pas déçus.
Test verdict: "Chez Noctua le maitre mot est qualité, et encore une fois cela se voit sur les derniers ventilateurs de la marque." (Christian Marchini, Conseil Config)
10.08.2017 // WhatNext.pl
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NF-A4x20 5V PWM Review

Wszystkie wentylatory oraz akcesoria są godne polecenia. Noctua ponownie pokazuje, że umie zrobić świetne konstrukcje. Śmigła są wydajne i prezentują się dobrze pod względem kultury pracy. Także jakość wykonania stoi na najwyższym poziomie. Podobnie jest z akcesoriami – świetne wykonanie i odpowiednie działanie.
Test verdict: "W zakupie sprzętu przeszkadzać może jedynie cena, która jest spora. Jednakże znakomite produkty nie mogą być tanie bo było by zbyt pięknie." (Michał Andruszkiewicz, WhatNext.pl)

NA-FC1

  • Compact, highly flexible controller for 4-pin PWM fans
NF-A4x20 5V PWM

NA-SEC1

  • 4-Pin Extension Cables
NF-A4x20 5V PWM

NA-SAV4

  • 16 NA-AV4 silicone anti-vibration mounts for up to 4 fans
  • Flat case-side end for clean exterior look
  • 5 defined, numbered pawls
  • Compatible with all Noctua fans
NF-A4x20 5V PWM

Installation Manual (PDF)

Information Sheet (PDF)

What pin configuration do Noctua 5V fans use?

The pin configuration of Noctua 5V fans is identical to 12V fans:

5v pin configuration

Which Noctua fan or CPU cooler should I buy? How to choose the right model?

Not sure which Noctua product to buy? Our detailed buying guides for fans and CPU coolers help you to choose the model that works best for you.

How much torque should be used for fan screws?

Please use 0.6Nm to tighten fan screws. Make sure not to overtighten the screws as this may damage the fan frame.

Can Noctua fans be used to replace noisy stock fans in NAS devices?

Noctua fans such as the 40, 60, 80, 92 or 120mm NF-A series models are ideal for replacing noisy stock fans in NAS devices in order to make them quieter and thousands of users have managed to significantly reduce the noise levels of their NAS units this way. However, while it is easy and straightforward to replace the fans in some cases, it can be very difficult in others, so Noctua strongly recommends that users carefully research if it is possible to easily replace the fan(s) of their NAS device before purchasing a Noctua fan for this purpose. Some of the common issues that can occur when replacing NAS fans are:

  • Different pin assignment: Whereas Noctua fans use the standardised pin assignment for PC fans (see this FAQ for details), some NAS units use different assignments. For example, some devices have the power and GND or rpm and PWM pins swapped. Therefore please carefully verify that your NAS device uses the same pin assignment as standard fans. Experienced users may also change the pin assignment by cutting and resoldering the fan cables, but please note that this will void your Noctua manufacturer’s warranty.
  • Different pin functions: Noctua fans use the standardised pin functions for PC fans (see this FAQ for details); however, some NAS units use fans where certain pins serve a different function. For example, some devices use the RPM pin for “power good” signals. Therefore please carefully verify that your NAS device uses the same pin functions.
  • Firmware speed control: Some NAS devices demand a certain maximum or minimum fan speed. If the new fan doesn’t have the same or similar maximum or minimum speed, the device may display errors or even shut down.
  • Different starting voltage: Most NAS devices use voltage-based speed control. If the new fan has a higher starting voltage than the original fan, it may not start up right away. This may lead the NAS device to display errors or even shut down because it suspects a fan failure.
  • Different power draw: Some NAS devices monitor the fan’s power draw. If the new fan has a lower power consumption than the stock fan, the device might display errors or even shut down.

Please note that most NAS manufacturers don’t provide detailed documentation regarding fan compatibility and control, so users who want to replace the fans of their devices usually have to rely on “How to” guides, blog and forum posts or video tutorials. For example, there are excellent video tutorials available for changing the fans in popular Synology NAS models (DS416j, DS1515+ and DS1812+ in English, DS416/DS415/DS916/DS216/DS214 and DS1515+ in German). Please also note that fan compatibility and control can vary from model to model and even from revision to revision even if the devices stem from the same manufacturer. As a result, it is important to make sure that the information or guidelines you rely on when replacing your NAS fan are applicable to your specific model as well as your specific hardware and firmware revision.

Due to the possible issues listed above, Noctua recommends that only experienced users attempt to replace their NAS fans. Please note that since there are so many different NAS models and most of them lack documentation for aspects such as fan compatibility and control, Noctua customer support cannot assist you with compatibility issues when replacing NAS fans. Please contact your NAS manufacturer for any questions regarding aspects such as the device’s pin alignment or fan monitoring and control.

Can Noctua fans be used to replace noisy stock fans in switches, routers or other network devices?

Noctua fans such as the 40, 60, 80 or 92mm NF-A series models are ideal for replacing noisy stock fans in switches, routers and other network devices in order to make them quieter and thousands of users have managed to significantly reduce the noise levels of their units this way. However, while it is easy and straightforward to replace the fans in some cases, it can be very difficult in others, so Noctua strongly recommends that users carefully research if it is possible to easily replace the fan(s) of their network device before purchasing a Noctua fan for this purpose. Some of the common issues that can occur when replacing pre-installed fans are:

  • Different pin assignment: Whereas Noctua fans use the standardised pin assignment for PC fans (see this FAQ for details), some network devices use different assignments. For example, some devices have the power and GND or rpm and PWM pins swapped. Therefore please carefully verify that your device uses the same pin assignment as standard fans. Experienced users may also change the pin assignment by cutting and resoldering the fan cables, but please note that this will void your Noctua manufacturer’s warranty.
  • Different pin functions: Noctua fans use the standardised pin functions for PC fans (see this FAQ for details); however, some network devices use fans where certain pins serve a different function. For example, some devices use the RPM pin for “power good” signals. Therefore please carefully verify that your device uses the same pin functions.
  • Firmware speed control: Some network devices demand a certain maximum or minimum fan speed. If the new fan doesn’t have the same or similar maximum or minimum speed, the device may display errors or even shut down.
  • Different starting voltage: Most network devices use voltage-based speed control. If the new fan has a higher starting voltage than the original fan, it may not start up right away. This may lead the device to display errors or even shut down because it suspects a fan failure.
  • Different power draw: Some network devices monitor the fan’s power draw. If the new fan has a lower power consumption than the stock fan, the device might display errors or even shut down.

Please note that most network device manufacturers don’t provide detailed documentation regarding fan compatibility and control, so users who want to replace the fans of their devices usually have to rely on “How to” guides, blog and forum posts or video tutorials. Please also note that fan compatibility and control can vary from model to model and even from revision to revision even if the devices stem from the same manufacturer. As a result, it is important to make sure that the information or guidelines you rely on when replacing your fans are applicable to your specific model as well as your specific hardware and firmware revision.

Due to the possible issues listed above, Noctua recommends that only experienced users attempt to replace their pre-installed fans in network devices. Please note that since there are so many different devices and most of them lack documentation for aspects such as fan compatibility and control, Noctua customer support cannot assist you with compatibility issues when replacing pre-installed fans. Please contact your network device manufacturer for any questions regarding aspects such as the device’s pin alignment or fan monitoring and control.

Can I use Noctua fans in my system from Acer, Apple, Dell, HP, Lenovo or other major brands?

Noctua 12V fans comply with the established specifications for standard PC systems issued by Intel and AMD. Systems from Acer, Apple, Dell, HP, Lenovo or other major brands often deviate from these specifications e.g. by using proprietary fan headers, custom pin-alignments or pin-configurations, different methods of fan speed control, etc. This can lead to compatibility issues when using Noctua fans in systems from said brands. Some of these problems can be avoided with some technical knowledge, but especially BIOS related issues (e.g. errors or shutdowns due to low fan speed) can often not be resolved. As a result, Noctua does not officially support systems from Acer, Apple, Dell, HP, Lenovo or other major brands.

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.

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!

D15S

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.

What pin configuration do Noctua 12V 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:

pin configuration

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).

Can I disassemble my fan for cleaning (or other purposes, e.g. painting)?

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.

Where can I find a technical documentation and specifications of the PWM speed control system of Noctua’s fans?

While using PWM (Pulse Width Modulation) based fan speed control in PC environments is usually straightforward and does not require any background knowledge, it can be vital when it comes to controlling fans via PWM in other environments. Please refer to our specification white paper for a detailed technical documentation of the PWM speed control features of Noctua’s 4-pin PWM fans. Detailing aspects such as connector types, pin configuration or RPM speed signal output as well as signal specifications and circuit design questions, it enables engineers to implement PWM based speed control for Noctua fans in custom circuit designs and applications.

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