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NF-S12A FLX 12V 1200RPM 120mm Flexible Ultra Quiet Cooling Fan
21 in stock
(35 customer ratings / 2 reviews)

Noctua NF-S12A FLX 12V 1200RPM 120mm Flexible Ultra Quiet Cooling Fan

The NF-S12A marks the third generation of Noctua’s signature S12 series quiet case fans, which have received more than 250 awards and recommendations from the international press.


  1. Noise levels from only 7.4 dB(A)
  2. High 63.27 CFM airflow
  3. Advanced Acoustic Optimisation Frame
  4. Three speed settings for maximum quietness
  5. Smooth SSO-Bearings
  6. Six year warranty

Featuring a further refined blade design with Anti-Stall Knobs that works in tandem with the new AAO or Advanced Acoustic Optimisation frame. The NF-S12A improves the airflow/noise efficiency of its renowned predecessor by up to 8%. The FLX version provides 1200 / 900 / 700 rpm speed settings via the supplied Low-Noise Adaptors in order to give you full flexibility in fine-tuning the fan for maximum ventilation performance or near-silent operation. Its superb running smoothness, SSO2-Bearings and Noctua’s trusted premium quality make it an elite choice for quiet case cooling.

Noctua’s Advanced Acoustic Optimisation 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.

Advanced Acoustic Optimisation Frame
Advanced Acoustic Optimisation Frame

Anti-stall Knobs: What is Stall?

Noctua’s S12 series fans impellers use a high angle of attack in order to achieve superior airflow. However, impellers with high angles of attack are typically more prone to undesired stall and flow separation phenomena that can occur when the fan is working against higher impedance such as when blowing through tight fan filters or when used on heatsinks and radiators.

What is Stall?
What is Stall?

In these situations when the fan is building up high pressure but less air is moving through, the speed of the air particles flowing alongside the suction side of the fan blades gradually decreases towards the trailing edge. The lower the speed and the higher the counter-pressure, the higher the risk of the air particles becoming detached from the blade surface. This flow separation phenomenon known as stall leads to undesired turbulence, reduced efficiency and translates into a dent in the fan’s performance curve.

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.

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-S12A remarkably quiet even at very close distance.

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

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.

Package Contents

As expected from Noctua, the fan is well packaged and is supplied with both the usual fan mounting screws and also rubber fan mounts to isolate the fan from the case ensuring that no vibrations from the fan can reach the case. Two in-line resistors are also included and these simply lower the voltage and therefore the speed of the fan if full speed isn't required. A Molex adapter allowing you to power the fan from the PSU and an extension cable are also included.

Additional Images

SpecificationsNF-S12A FLX
Size120 x 120 x 25 mm
Blade GeometryS-Series with Anti-Stall Knobs
Rotational Speed ±10%1200 PRM
Rotational Speed with L.N.A. ±10%900 RPM
Rotational Speed with U.L.N.A. ±10%700 RPM
Airflow63.3 CFM
Airflow with L.N.A.49.0 CFM
Airflow with U.L.N.A.38.7 CFM
Acoustical Noise17.8 dB(A)
Acoustical Noise with L.N.A.10.7 dB(A)
Acoustical Noise with U.L.N.A.7.4 dB(A)
Static Pressure1.19 mm H2O
Static Pressure with L.N.A.0.73 mm H2O
Static Pressure with U.L.N.A.0.51 mm H2O
Input Power1.44 W
Input Current0.12 A
Voltage Range12 V
MTBF> 150.000 h
Warranty72 months
EAN barcode4716123314905

Customer Reviews

To PWM or not to PWM?


These are nice fans, easy to install, and do the job. They are quiet, and the noise is a steady "whoosh...", so is quite pleasant. Unlike reviewer Misic, I think I'd prefer to have fans which go slow when not much is happening - maybe not surging up and down quickly of course, but rather mostly running slow and ramping up only for high-temperature processes.

In that sense, I believe I would have been better off with PWM fans, where my motherboard (Gigabyte Z87X-UD3H) can control them; the BIOS utility or SpeedFan is unresponsive for 3-wire fans like this. That's personal taste, but other buyers might want to think harder about this issue than I did before opting for FLX or ULN rather than PWM versions. Like the other reviewer, I also had warnings emitted from the mobo about fan status, but found that I could switch those off in BIOS.

First impressions


I purchased NF-S12A FLX, to use it as the main and only case fan (rear exhaust) for my "Sonata 2". I haven't tried it without low-noise adapters because my current cooling needs are completely fulfilled on its slowest setting (with ultra-low-noise adapter, just over 700 rpm).

It seems to me that regardless if connected through its low-noise or ultra-low-noise adapter, it doesn't add-up any sound over the hum generated by air passing through "NH-D14" pushed by its stock "NF-P14" and "NF-P12" both connected through their low-noise adapters, respectively. The PSU is in hybrid mode so it was absolutely inaudible (no "coil whine"), and there was no dedicated graphic adapter card, during test.

Both of NF-S12A FLX low-noise adapters are perhaps a bit confusingly labelled "Low-noise adapter"! Only enigmatic markings NA-RC10 (for Low-Noise) and NA-RC12 (for Ultra-Low-Noise) differentiate them, and explanation what is what in installation manual is in such fine (small) print, that is not friendly to those with imperfect eyesight...

NF-S12A FLX has much shorter connection cable compared to old NF-S12B FLX, but it is bundled with long extension cable, which should provide more flexibility with cable management.

I do use NF-S12B FLX since 2010, in my other PC ("Sonata 3 - 500" case) in the same role of rear exhaust. Unfortunately, I cannot directly compare them because of differences in set-ups. Stock "EA500-D" PSU noisy fan swamps the sound of stock "NF-P14" (on top of the "NH-C12P SE14") and "NF-S12B FLX" both connected through their low-noise adapters, respectively.

I do belong to the niche segment that is more annoyed by RPM changes, than by the absolute noise generated by fans. So I repeated my lazy concept of acquiring the constant-speed fan, instead of researching ways to make the PWM controlled fan rotate steady on desired speed. To my unpleasant surprise, I now learned that my MB (Gigabyte) has specific voltage control on its "system fan" connectors. Thus, when NF-S12A FLX is connected through any of its low-noise adapters, it causes a short fan-fail warning beep, because it fails to spin-up immediately during boot-up sequence. It is only for a fraction of a second (before MB sends full voltage to the "system fan" connectors), but it does create annoying beep for every boot-up! NF-S12A FLX does come bundled with 4-pin Molex adapter for connecting it directly to PSU, but that "solution" eliminates the potentially useful fan-failure warning feature


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