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Noctua Straight-Blade-Design
Current silent fans frequently employ conventional blade geometries, which were developed for higher speed ranges and significantly lose efficiency at lower rotation speeds. The Noctua Straight-Blade-Design of the NF-S12 series was developed by the Austrian Institute for Heat-Transmission and Fan Technology (Österreichisches Institut für Wärmeübertragung und Ventilatorentechnik, ÖIWV) and specifically tailored to 120mm fans with extremely low rotation speeds. The result is a performance improvement of up to 10% and more compared to conventional blade geometries.

    The Straight-Blade-Design of the NF-S12 series provides the maximum efficiency of a straight fan blade without the drawback of higher noise emission, which arises when straight blades are used at higher rotation speeds. At the low rotation speeds of the NF-S series, the Noctua Straight-Blade-Design achieves a significantly higher flow rate than forward or backward swept blade designs. Furthermore, among other measures to prevent vortices like the rounded rotor hub, the distance between rotor and stator (tip clearance) was increased in order to reduce the problem of tip vortices which plays an important part in the noise emission of axial fans. With its fan blade exactly tailored to ultra low noise application, the NF-S12 series is significantly more quiet than other high end silent fans.

    Mag. Manfred Stadler MBA of the Austrian Institute for Heat-Transmission and Fan Technology (Österreichisches Institut für Wärmeübertragung und Ventilatorentechnik, ÖIWV) about the development of the Noctua Straight-Blade and Raised-Blade-Designs:

    "In the area of PC cooling, the last years saw a growing demand for axial fans with the lowest possible noise emission, which manufacturers mostly met by simply reducing the RPM of existing models without sufficiently adapting the blade geometry and profile to the modified fluid dynamic parameters. The comparison of measured data and simulation outputs showed that the result was an average deficit of efficiency of 10-15%. The complete redevelopment of the blade geometry and profile was carried out with exact fluid mechanical adjustment to minimal noise emission in a speed range of 400-1800RPM at a height of 25mm and a radius of 40 and 60mm. Both fan blades possess 8-12% more flow rate than comparable products at the same total noise emission and static pressure." (Mag. Manfred Stadler MBA, Austrian Institute for Heat-Transmission and Fan Technology (Österreichisches Institut für Wärmeübertragung und Ventilatorentechnik, ÖIWV))

03.03.2015 - NH-D9L
Test verdict: "The Noctua NH-D9L packs alot of cooling in a little package. If you are needing to save the space but do not want to sacrifice performance the dual fan setup competes pretty close to the big behemoth coolers." (Chris McCart,

03.03.2015 - NF-A4x10 5V
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,

03.03.2015 - NH-U9S
Test verdict: "Given these height and footprint size restrictions, the Noctua NH-U9S is a pretty quiet heatsink that offers very good thermal performance in the sub-125mm tall heatsink category, making it an excellent choice for PCs which are severely space limited. The results are enhanced by adding a second fan, as we've shown over the course of this review. Couple that with awesome build quality and a 6 year warranty and it's not hard to recommend this cooler." (Max Page,

02.03.2015 - Hardwareluxx Community NF-P14s redux-1200 PWM
Test verdict: "Das Ergebnis dieses Reviews zeigt, wie effizient die Redux tatsächlich arbeiten. Auch wenn es sich hierbei nur um 0,15 bis 4,05°C handelt. Die Lautstärke ist bei voller Drehzahl im Vergleich zum TY-147A wesentlich geringer [...]. Für einen angemessenen Preis von ca. 13 Euro bietet Noctua einen erstklassigen und sehr qualitativen Lüfter." (Aliriza Tasdemir, Hardwareluxx Community)