Noctua 140mm/150mm Case Fan Roundup ReviewEl_Capitan - April 2, 2013
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Noctua 140mm & 150mm fan Closer Look:
Noctua NF-A14 ULN
The first thing I noticed when pulling the fan out for a closer look was the weight. It is a little bit heavier than the Noctua NF-P14. A few other things that stand out from the Noctua NF-P14: it has a square frame as opposed to a round frame, which is ideal for use on watercooling radiators as it ensures full coverage and best pressure performance. There's no longer a nine blade fan blade design with Vortex-Control Notches; they now have seven fan blades on the impeller without notches. On the back of the blades there's now these nifty Flow Acceleration Channels that are supposed to alter the flow distribution on the suction side of the blades. This is to speed up the airflow at the crucial outer blade regions leading to significant reduced flow separation, which permits lower vortex noise and higher airflow efficiency. The corners are now adorned with removable Anti-Vibration Pads to reduce vibration noise.
The outside of the frame is lined with what Noctua calls a Stepped Inlet Design. This design is also identical to the one used on the Noctua NF-F12 PWM. It adds turbulence to the fan's influx so the fan can suck in more air to improve flow efficiency. It's also designed to reduce tonal intake noises. The inside of the frame is dotted with Inner Surface Microstructures that are used to create a turbulent boundary layer when the fan blades pass by. This is to help improve airflow and static pressure efficiency while also allowing for again lower noise emissions. The Noctua NF-P14 had 120mm mounting holes (105mm spacing), which came with extensions for 140mm mounting. The Noctua NF-A14 ULN now has 140mm mounting holes (124.5mm spacing).
Noctua NF-A14 FLX
Externally the Noctua NF-A14 FLX is physically identical to the Noctua NF-A14 ULN aside from the front center sticker. Internally are where the differences lie in how the windings are set up to run at a higher operational speed of 1200RPM versus the 800RPM on the NF-A14 ULN. It is equipped with the same feature sets discussed with the NF-A14 ULN.
Noctua NF-A15 PWM
The Noctua NF-A15 PWM has all the enhanced features of the NF-A14's with the following additions. It has a round frame and the width is enlarged to 150mm while still being 140mm in height. It's a little confusing as it's not intended as upgrades to 140mm fans, but instead is intended for upgrades to 120mm fans for use on high-end CPU coolers and case fans. The Noctua NF-A15 PWM has 120mm mounting holes (105mm spacing). It has a custom designed NE-FD1 PWM IC that is fine-tuned for superior quietness and has been carefully optimized to allow for ultra-low power consumption.
Included in the A14 and A15 fans, but behind the scenes, is the new SSO2 Bearing Technology. Noctua states that, "SSO2 is the further optimized second generation of SSO. Made possible by the use of metal bearing shells and new injection molding techniques, the magnet is now placed closer to the rotor axis and thus exerts higher magnetic force to it. This results in even better stabilization, precision and durability." I'll take Noctua's word for it. All this innovation and design sounds great on paper, but let's see how that equates to real-world testing.