Page 2 - A Closer Look - Hardware
One thing about Noctua is their usual color scheme for their fans; however, these are mostly black except for the corners. There are possibly two reactions to this. One side could say it makes the aesthetics of their case better. On the other hand, nobody will be able to quickly distinguish you have Noctua fans. I am happy for the change in color, especially since the brown corners can be changed to a wide variety of other colors with the anti-vibration pads. On the left and right side are the 120mm fans in our photo above, while in the middle are the two 140mm versions. Here, you can also see the white anti-vibration mounts and pads. As you can see, the bundle is simple, with just the fan and four screws included. The box folds open revealing the fan, while the cardboard cutout on the inside can be removed, where the four screws and the cable are tucked away. I like simple packaging, as it makes the entire process easier.
The internals and design of these fans are all the same. The only difference between them are their max RPM range and size. They all feature Noctua's SSO2 bearing, which is a self-stabilizing oil-pressure bearing. This is different from the usual bearings found in other fans, such as sleeve and ball bearing. Noctua's SSO2 bearing uses oil-based hydrodynamic bearings with a magnet that stabilizes the rotor axis. The company claims this to be more silent with better longevity than the other methods, and if previous products are anything to go off, they have achieved it. SSO2 features a metal shell, and the magnet is closer to the rotor axis than the original version, which results in better stability and longevity. These fans also feature a three-phase motor with six slots, as opposed to the standard single-phase motor with four slots. Noctua guarantees this motor provides smoother transitions between the slots, which reduces vibration and results in better energy efficiency.
There are quite a few extra design choices to ensure the best performance from these fans. Both the frame and the impeller are made from fiberglass reinforced polyamide, which makes them really robust. Along with an IP67 rating, it is dust resistant and waterproof up to one meter in depth. They are 24V versions, but they can work with 12V in a PC environment, and with the lower voltage, they are capped at 1800 RPM. Noctua's AAO (Advanced Acoustic Optimization), also features integrated anti-vibration pads. All these will improve the noise emissions of the fans that we have all come to expect from Noctua. The frame also has a stepped inlet design to add turbulent airflow, which reduces intake noise, improves flow attachment, and increases suction capacity. Another new feature are inner surface microstructures. They are small, almost-dot like patterns on the inside of the frame to reduce noise with better airflow and pressure efficiency. All fans are equipped with braided cables.
All four of the fans are pulse-width modulation, abbreviated as PWM, fans. They connect to a four pin header on the motherboard. Since these fans can take up to 24V, but within a PC the maximum would be 12V, the maximum speed will then be reduced to 1800 RPM. For sound, airflow, and static pressure technicalities, the following section has been borrowed from Editor-in-Chief Jonathan Kwan's review of the NF-F12 PWM and NF-P12 PWM fans.
Noise and CFM relates to the big challenge when designing fans is to provide the best airflow to noise ratio. One would want the best amount of airflow, while keeping it as quiet as possible. Even with the best ratio, it is quite difficult to measure objectively at all times. The most common unit of objective measurement is CFM (Cubic feet per minute) of air for airflow, and dB noise, respectively. We will go over how application and CFM is related with regards to its standard measurements, but let us discuss perceived noise first.
dB (Decibels) is a logarithmic unit of sound intensity. While it provides what appears to be an objective measurement for the most part, it should be noted that perceived noise levels to the human ear, and actual sound intensity, could result in very different things. Human ears are more sensitive to particular frequencies, and when those particular frequencies are emitted from its source, it may appear louder than its numbers suggest. That same can be said vice-versa -- frequencies that human ears are less sensitive to can actually have louder dB measurements from a sound meter, yet the human ears does not perceive it to be as loud as the numbers suggest. Other factors such as turbulence noise are often not measured correctly, therefore, while it usually provides a good reference, it does not necessarily reflect real life performance.
With regards to the application and CFM, it is generally optimal to have a fan to have a high air volume flow rate -- but as aforementioned, pure CFM values are limited to an extent with regards to its indication on fan performance. It is not completely about how much air in can move per minute quantitatively, but equally as important is how it is executed in reality. Airflow to noise ratio is an essential factor as mentioned earlier. Static pressure is also very important depending on application. High resistance applications such as dense fins on a large heatsink require high static pressure, while case fans needs less static pressure and faster airflow. There are times where case fans will require higher static pressure too, such as the frontal intake fans, where a mesh grille would create some resistance. The differences in application is like a large truck that has a diesel engine with lots of low end torque for towing, compared to a sports car with a high revving gasoline engine with lots of power to beat around the track -- they are simply designed for different purposes, so choose one appropriate to your needs.
The technical numbers of the two different models differ quite a bit. The Noctua NF-A14 IndustrialPPC PWM airflow is rated at 269.3 m³/h, and the acoustical noise at 41.3 dB. The static pressure is 10.52mmH2O. On the other hand, the Noctua NF-F12 IndustrialPPC PWM has airflow rated at 187.7m³/h, acoustical noise at 43.5 dB, and static pressure at 7.63mmH2O. With all these numbers, I think it would be best to see some actual results. On the next page, we will be testing the fans with the APH proprietary 'scientific' method first presented in 2007.
There are two anti-vibration products to keep sound output even lower. The NA-SAVP1 are the anti-vibration pads, and they are compatible with quite a few of Noctua's most popular fans. They have a list on their website for the full information on all the different models these pads can be attached to. The NA-SAVP1 have six different colors to choose from to best match your build. The colors available are black, blue, green, yellow, red, and white. With six different choices, it should match the aesthetics of your case. To further reduce sound, Noctua has made the NA-SAV2, which are the anti-vibration mounts, featuring all the same colors as the NA-SAVP1. They are very easy to use and to install. If you happen to use them on a rear exhaust fan, they do stick out just a bit, which could look funny to some people. All pads are made from silicone, making them tear proof and very soft to help reduce any vibrations. Both the NA-SAVP1 and NA-SAV2 fit their intended design well in my opinion.
1. Introduction, Packaging, Specifications
2. A Closer Look - Hardware
3. Performance Tests