Noctua for 92

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The Noctua NF-B9 comes in the usual colours for Noctua; a brown, black and blue getup. The front of the package has a small window where you can see the fan and its funky shaped fins before you buy. The rear of the box gives you the low-down on all the ridiculous enhancements that Noctua have made to the basic fan template, including bevelled blade tips and vortex control notches. If you need more information, along with fairly technical diagrams, you can pop open the guide on the back of the box to let you know.

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That said, it contains such sentences as, ‘This measure makes it possible to combine the large blade surface area and high profile chord length of a high-output blade geometry with excellent quietness of operation.’ If you know what that means, you probably have the know-how to make your own fan, but it’s nice to see Noctua trying to communicate what they’ve done.

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The fan comes with the wide range of bits and pieces I’ve come to expect from Noctua, which includes four standard case mounting screws, four anti-vibration pegs, the Ultra Low Noise Adaptor (ULNA), the Low Noise Adaptor (LNA) and finally a 3-pin to molex converter. If you’ve never read one of our Noctua fan reviews, you won’t have heard about the MULNAZ adaptor which has become a word used to describe something that is truly quiet; read more here. The two adaptors lower the fans speed from the stock 1600 RPM (37.8CFM @ 17.6 dBA) to 1300 RPM (30.9 CFM @ 13.1 dBA) for the LNA and 1000 RPM (24.2 CFM @ 7.9 dBA). Wait, read that again… 37.7 CFM at 17.6 dBA?? Those kind of values are normally associated with the large 120mm fan market. Note, these values are converted from Noctua’s odd meters cubed per hour figures quoted, do the conversion for yourself on Google here.

More importantly than flow rate, is the static pressure of the fan. Static pressure refers to the force at which the blown air exits the fan at. A lower static pressure will mean that the CFM will take a nose-dive if you were to use the fan behind, say, a watercooling radiator as the additional resistance of the radiator fins obstructs airflow. As a result, static pressures gives you an idea of the fans ‘power’ and the workload that it can achieve. The NF-B9 can achieve a maximum of 1.61 mm in water, and down to 0.64 mm in water when using the ULNA.

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The fan itself comes in the usual peach and brown colours that Noctua have soldiered on with regardless of whether people would prefer a black colour. To me, the Noctua colour scheme makes them easily identifiable, and the fact that they still sell is a testament to how they work, rather than how they look.

This fan comes complete with bevelled blade tips which to my knowledge haven’t been used on any of the previous Noctua fans. The bevelling takes places on the ends of each of the 7 fins and increases the distance between the fins and the stator or fan housing. This apparently lowers the noise output in comparison to a similarly rated CFM fans.

Of course the fan uses Noctua’s SSO (self-stabilising oil-pressure bearing) which uses hydrodynamic pressure along with the magnetic field created by the rotor; and yes I have no idea what this means, but it amounts to a quieter and longer lasting bearing being up to three times quieter than the standard sleeve type. It must last a while as Noctua offer a massive 6 year warranty on their fans.

The rotor is powered with Noctua’s SC drive which reduces the sudden increase in torque you get when the magnetic driving force has its polarity switched. All motors run on the idea of a magnetic force pushing the rotor around, and then switching polarity so it’s propelled round for the next half-turn. Just as the polarity is switched, there is an increase in torque which speeds the rotor up slightly, creating unwanted noise. The SC drive apparently lowers these torque variations which are more apparent at lower speeds where the polarity changes less often as the rotor is turning slower.

The last type of technology you’ll find on this and not a generic blower, are the vortex control notches. These are placed in such a position that they split the trailing vortex’s created by the fin moving through the air, so it doesn’t make the fan quieter per se, but spreads the noise over a wider spectrum so the pitch is more comfortable.

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The fan itself has a sleeved wire tail that terminates in a 3 pin fan header, meaning that you won’t have to route a molex cable to it in order to give it power. However, if you are fresh out of mobo headers, then the provided molex to 3 pin converter will be just what you need. This is by far the best way to package fans as you’ll be able to monitor PWM values, and also easily use them with your fan controllers should you have one.

The anti-vibration pegs are made of some kind of stretchy rubber which allows you to not only lower the amount of vibration passed from fan to chassis, but also means that you can mount the fan without the use of a screwdriver.