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The NF-A9 is a highly optimised, premium quality quiet 92mm fan. Featuring Noctua’s AAO (Advanced Acoustic Optimisation) frame as well as sophisticated aerodynamic design measures such as Flow Acceleration Channels, the NF-A9 further improves the renowned quiet cooling performance of the award-winning NF-B9. 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 2000 to 1550rpm. Its superb running smoothness, reference-class SSO2 bearing and Noctua’s trusted premium quality make it an elite choice for the highest demands.

Details
Succeeding the award-winning NF-B9

Succeeding the award-winning NF-B9

Noctua's NF-B9 fan has become a default-choice among PC enthusiasts looking for a premium quality quiet 92mm fan. Thanks to its thoroughgoing aerodynamic optimisations, the NF-A9 provides higher static pressure and an even better airflow/noise ratio than its much acclaimed predecessor.
Flow Acceleration Channels

Flow Acceleration Channels

The NF-A9 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 screws and other mounting systems.
SSO2 Bearing

SSO2 Bearing

The NF-A9 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-A9 PWM uses Noctua's novel, 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-A9 PWM is supplied with a (L.N.A.) that reduces the maximum fan speed from 2000 to 1550rpm. The L.N.A. can be used either to run the fan at a fixed speed of 1550rpm 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-A9 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-A9 features an MTTF of more than 150.000 hours rating and comes with a full 6-year manufacturer’s warranty.
NF-A9 PWM
FAN Specification
Size
92x92x25 mm
Mounting hole spacing
82,5x82,5 mm
Connector
4-Pin PWM
Bearing
Blade Geometry
Rotational Speed (+/- 10%)
2000 RPM
Rotational Speed with L.N.A. (+/- 10%)
1550 RPM
Min. Rotational Speed (PWM, +/-20%)
400 RPM
Acoustical Noise
22,8 dB(A)
Acoustical Noise with L.N.A.
16,3 dB(A)
Static Pressure
2,28 mm H₂O
Static Pressure with L.N.A.
1,53 mm H₂O
Max. Input Power
1,2 W
Max. Input Current
0,1 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-A9 PWM
A-Series fans
10.05.2014 // Vortez.net
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NF-A9 PWM Review

+ They are quiet fans.
+ They have pretty good output for being so quiet.
+ They come in resilient packaging.
+ They come with well-chosen accessories.
Test verdict: "Noctua started with really good fans, and made them better. One thing that strikes you if you handle the old fans is that they are very good fans, so it makes sense that Noctua still sells them in their redux line. But these A-Series fans are even better, and well can they join their big brothers in the A-Series lineup." (Ed Hume, Vortez.net)
03.03.2015 // PureOverclock.com
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NF-A9 PWM Review

As always, sound levels are superb with these fans. While my opinions are subjective, what I found was after 45 dBs, that’s when I felt a fan was getting too noisy. Nothing about the Noctuas sounded too loud while testing them even at max speed, but with the plethora of LNAs and ULNAs to add to the fans, even if you didn’t have a way to control the fans it was unlikely you couldn’t tone them down to where you would be happy with them.
Test verdict: "Overall, I believe Noctua makes an excellent product. There really isn’t anything I can complain about except for the price, and even then the price is understandable. If you need good air flow, low noise and have a small form factor case that needs some better fans, I could definitely recommend what Noctua has to offer here." (Josh Jackson, PureOverclock.com)
09.02.2015 // QWERTYmag.it
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NF-A9 PWM 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)
07.01.2015 // Neoseeker.com
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NF-A9 PWM Review

After studying the Noctua A-series Premium fans for the last few weeks, I have begun to understand how each design feature performs their function. As noted in the following paragraphs, each feature adds to the overall function of noise reduction, therefore improving air flow and performance efficiency. The Noctua Advanced Acoustic Optimization Frame has anti-vibration pads in each mounting flange corner. This feature not only reduces vibration noise transferring from the fan, but also into the fan from wobbly case components. The Stepped Inlet Design on the fan case edge turns the air flow from laminar to turbulent, reducing the tonal intake noise. The Inner Surface Microstructures next cause a boundary layer to reduce suction side flow separation as the fan blade tips pass, reducing the blade passing noise with improved air flow. The Flow Acceleration Channels on the fan blades cause the outer blade region air flow to speed up, reducing vortex noise of the fan blades while improving efficiency. Moving the magnet of the Noctua renowned SSO Bearing closer to the axis of the bearing improves stabilization, precision and durability. All of these features and more are packaged with many accessories for each fan, plus Noctua provides a 6 year warranty.
Test verdict: "Noctua A-series Premium fans are looking like the right choice for your new or replacement case fan." (Marvin Purdy, Neoseeker.com)
14.11.2014 // Modders-Inc.com
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NF-A9 PWM Review

Aside from the lower temperature, the A9 fans have a more “spread out” sound signature even though it is running at a higher RPM and has lesser high pitched noises across various speeds. The extra padded corners also help in giving extra space when positioned in a “pull” position minimizing noise. The smaller form factors and compact builds are much more common now than ever before with many users opting to build desktops that can be portable for LAN parties or for discreet integration in their living room as an HTPC. The A9 and A8 series fans fit these application well with excellent performance and low noise profiles that is even more flexible if need be. For storage or, spot cooling or component cooling in even tighter spaces, the A4 series offers a rare and impressive feature set that is above what most people would expect from something this small.
Test verdict: "These A-series fans also enjoy the same set of low noise features and premium build quality that the other Noctua fan series provides, including the impressive 6-year warranty and extensive accessory package." (Ron Perillo, Modders-Inc.com)
11.05.2014 // Hardware-360
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NF-A9 PWM Review

Stock performance shows a 3 degree drop with the A9 fans on heatsink use and up to 2 degrees under FPU only loads. Noise performance is superior in the NF-A9, despite the higher RPM with a smoother PWM operation and lesser high pitched noises across various speeds. The extra padded corners also help in giving extra space when positioned in a pull position minimizing noise. Ultimately each fan size has its own application depending on the chassis or heatsink applied to, although the smaller A4 5V fan is more suitable for storage cooling but will not look out of place as a chipset or spot cooler as well, especially the 12V version for added flexibility. The 92mm and 80mm A9 and A8 have a very balanced performance as both heatsink fans or case fans with their wide fan blade and excellent static pressure performance. The further lowered noise compared to the B9 and R8 series is a welcome change because the original fans were not particularly troublesome at all when it came to noise either. The integrated padded corners also work very well for noise dampening, especially when positioned as a “pull” fan since there is an added space that minimizes high pitched noises typically present in high-RPM performance fans when placed in this position.
Test verdict: "As with all Noctua fans, they come with premium pricing as they come in premium packaging and feature set so they are not easily affordable. The good thing is that the 6-year warranty found on larger Noctua fans also apply to the A9, A8 and A4 series, as well as the premium accessories that come out of the box." (Ron Perillo, Hardware-360)
14.05.2016 // Vmodtech.com
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NF-A9 PWM Review

วันนี้ในการทดสอบผมลองต่อทดสอบกับเมนบอร์ดโดยตรงครับ โดยผมวัดแรงลมนี่โอเคเลยครับสำหรับ Airflowแม้จะเป็นพัดลมตัวเล็กๆแต่แรงลมนี่หายห่วงครับเย็นจริงๆแต่ตามที่สเปกเคลมไว้จะอยู่ที่ 78,9 m³/h ครับ ส่วนถ้าใช้งานกับระบบ L.N.A.จะอยู่ที่ 62,6 m³/h ครับ ในส่วนของเสียงรบกวนอันนี้ต้องบอกเลยครับของเค้าเงียบจริงๆ ซึ่งผมได้หยิบมาฟังข้างๆหูนี่ก็เบามากๆเลยครับเงียบมากจริงๆสมกับที่ฟีเจอร์ที่ชูจุดเด่นเรื่องเสียงรบกวนครับ จุดเด่นอีกอย่างก็คือตัวยางทั้ง 4มุมกันกระแทกที่ช่วยซัพแรงและลดเสียงรบกวนได้เป็นอย่างดีครับ
Test verdict: "ก็มาถึงบทสรุปนะครับสำหรับการทดสอบ Noctua NF-A9 PWM ที่ วันนี้ถือว่าทำประสิทธิภาพได้ดีมากเลยครับทั้งในเรื่องของความแรงของพัดลมที่แรงดีจริงๆรวมไปถึงเสียงรบกวนที่ทำออกมาได้สวนทางกับความแรงของพัดลมที่เรีกได้ว่าเงียบจริงๆ กับดีไซน์ที่เน้นเอกลักษณ์ของยี่ห้อ Noctua ในโทนสีครีมตัดน้ำตาลก็ดูดีสวยงามไปอีกแบบครับ แม้ว่าตัดพัดลมจะไม่ได้มีแสงสีอะไรมาให้แต่มองดูรายละเอียดของงานแล้วถือว่าเนี๊ยบมากครับ ในส่วนของอุปกรณ์พวกสายเชื่อมต่อต่างๆก็มีมาให้แบบครบครันครับทั้งสายต่อพ่วง ต่อแยก หรือแม้กระทั่งสายต่อระบบ Low-Noise Adaptor ที่ช่วยเน้นเสียงรบกวนที่เงียบจริงๆ ถือได้ว่าเป็นพัดลมขนาด 92mm ที่เน้นประสิทธิภาพการใช้งานที่ครบครันเหมาะกับท่านทีกำลังมองหาพัดลมประสิทธิภาพเยี่ยมที่ทั้งแรงและเงียบไว้ใช้งานผมมองว่า Noctua NF-A9 PWM ตัวนี้น่าสนใจเป็นอย่างมากครับ โดยราคาวางจำหน่ายอยู่ประมาณ 5XX บาทไทยครับ สำหรับวันนี้ผมก็ขอตัวลาไปก่อน สวัสดีครับ" (Vmodtech.com)
04.04.2016 // ITNdaily.ru
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NF-A9 PWM Review

С одним вентилятором на борту Noctua NH-D9L способен отвести пыл от Intel Core i5-6600K на 4900-5000 МГц. Оптимальным и относительно холодным вариантом является показатель в 4700-4800 МГц. Пропеллер при этом не работает на максимальной скорости.
Test verdict: "Noctua NH-D9L и вентилятор Noctua NF-A9 PWM оставили исключительно положительные впечатления, с такими продуктами приятно работать. Рекомендуем не обходить стороной данные устройства, если такая возможность существует." (Евгений Никифоров, ITNdaily.ru)
04.02.2016 // SmallFormFactor.net
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NF-A9 PWM Review

All in all, these products are well built, well designed, and are able to achieve specs that by-and-large merit the premium price asked of them. None of the tested fans exhibited loud operation, and the included accessories ensured that the fans can be used in many different systems.
Test verdict: "It is typical for high-end or “luxury” goods to embrace a brand, style, or ethos, and Noctua does precisely that with their distinctive color scheme. The rest comes down to performance, though, and while you’ll pay top dollar to install a Noctua fan in your build, we’re hard-pressed to imagine how anyone will find themselves disappointed." (John Morrison, SmallFormFactor.net)
02.11.2015 // Hardaily.com
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NF-A9 PWM Review

Los ventiladores Serie A de Noctua están recomendados por Hardaily como ventiladores suplementarios (versiones no PWM), sustitutos de ventiladores más modestos o viejos para lograr mejor ventilación. Las versiones PWM son altamente recomendadas por Hardaily como sustitutos en los disipadores o radiadores y para que tengan autocontrol, ya que son los más potentes también. Todos ellos son perfectamente válidos para torres, servidores, para disipadores o incluso radiadores, siempre que sean compatibles con las medidas estandarizadas de 4 8 y 9cm. Todos estos ventiladores de Noctua son de los más duraderos y resistentes del mercado.
Test verdict: "Estos productos son prácticamente perfectos." (Raul Planelles, Hardaily.com)

Installation Manual (PDF)

Information Sheet (PDF)

The supplied y-cable is missing a wire at one of the two connectors, is it faulty?

No. As mainboards can process only one rpm-signal per fan header, it would cause problems if the cable transmitted rpm-signals of both fans. For this reason, one of the two connectors does not have an rpm wire and only the fan on the other connector will transmit an rpm signal. Automatic speed control of both fans will work independent from the second fan’s rpm signal.

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 (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.

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.

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).

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

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:

P14

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.

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

Noctua fans such as the 40, 60, 80 or 92mm 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 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.

I get a CPU fan error using my Noctua PWM fan, is it faulty?

Noctua PWM fans feature a minimum speed of 300rpm to allow for ultra quiet operation when your CPU is at idle state and doesn’t require higher cooling performance. Some mainboards display error messages such as “CPU fan error” during the booting process when the fan speed is below a certain level. If you get such error messages using your Noctua PWM fan and if such options are available in your BIOS, please either adjust the minimum fan speed monitoring limit to 200rpm or increase the minimum PWM duty cycle. If your BIOS doesn’t offer these options, please disable CPU fan errors. For detailed information on BIOS fan settings, please consult your mainoard’s manual or contact your mainboard manufacturer.

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

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). In this case, it may occur that the mainboard reduces the voltage so much that the fan stops. 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.



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.

  3. 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.

My Noctua PWM fan runs at a much higher minimum speed than advertised, what is wrong?

The specified minimum speed refers to the speed at 20% PWM duty cycle. There can be several reasons why the fan doesn‘t go as low as indicated:

  1. Many mainboards do not go below 40%, 50% or even 60% PWM duty cycle on case fan headers. Please refer to your mainboard manual to verify whether the fan header actually goes down to 20% duty cycle. If that's not the case, in some cases you can use the fan speed control software supplied with your mainboard to overcome these limitations and reduce the fan speed even further. However, 3rd party tools like SpeedFan offer greater flexibility and better options to work around the limitations imposed by the mainboard vendors.

  2. 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.

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).

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.

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