Noctua NF-S12B FLX

The name, NF-S12B ‘FLX’, refers to the flexibility version of the fan with theNF-S12B ULN also available for silent enthusiasts looking for very slow fan speeds. The FLX runs slightly faster with three different speed settings in order to allow the fan to be ‘fine-tuned’ for greater airflow or silent use.

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The NF-S12B range succeeds the highly successful NF-S12 and is intended for use with coolers with relatively large fin spacing and applications where quiet cooling is a priority: essentially they are the counter-part to the NF-P12 which is meant for more heavy duty use due its much higher static pressure.

The graph below displays nicely the balance between the NF-S12B and the NF-P12 fans.

The NF-S12B FLX has three speed settings: the stock speed of 1200RPM can be stepped down to 900 and 600RPM using the noise adaptors. This then enables the user to determine between lowest possible noise and highest airflow which at stock speed is 100.6 m³/h @ 18.1 dBA.

Another piece of technology which has been further developed and then implemented into the design is the Smooth Commutation Drive 2 (SCD2) which, in a nutshell, is to do with the Torque pulses sent out when a coil switches on. The SCD2 system aims to make the switching much smoother in order to reduce the noise levels.

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The motor for the NF-S12B fans features Noctua’s special SSO bearing technology that has been widely implemented into all of their latest designs. The concept involves using a magnet and pressure fields in order to stabilise the impeller so as to prevent extra turbulence being caused with can then add to the noise outputs.
Thus Noctua have marketed this bearing as being much quieter than the more conventional sleeve and ball bearings.

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Finally, we come onto the blade tips on the impeller which are much different from the standard tips seen on the NF-S12. Instead, beveling (effectively small notches) has been utilised to give a much smaller clearance to the frame at the leading edge.

The aim of this is to provide a better airflow to noise ratio and this is achieved due to the increased length of the blades. This then means that the velocity at the outer edge of the blades is higher and so more airflow is produced – Noctua claim up to 10% over the NF-S12.

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The overall advantages of the new technology are easily seen in the graph below with increased static pressure and airflow at a lower speed and thus lower noise levels. Altogether on paper it all looks very impressive.

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