Page 2 - A Closer Look - Hardware
Out of the box, there are a few things to note. Both the NZXT Aer F120 and F140 fans come with a long cable connecting the 4 pin PWM header. The cable is sleeved to hide the four wires, and it measures approximately 600mm in length, which is actually quite long, and should have enough length to maneuver around most cases. I did find the cables to be a bit stiff, but I think they are still flexible enough to bend around while protecting the thinner wires inside. Next, we have the four metal screws to mount the fans into the case. Finally, there is a low noise adapter to reduce the operating speed, and therefore the noise omitted by the spinning blades.
As for design, the NZXT Aer F fans seem to be a business-casual mix. The plastic frame and impeller are both black in color. There is a gray frame around the fan to provide a bit of contrast. However, if gray is not your style, these plastic frames can actually be popped out and swapped around with other colors such as red, white, or blue. All of these frames are sold separately. Otherwise, NZXT's logo is displayed on one side at the middle, while some certifications are printed on the other side. Typically speaking, fans are not really the flashiest of items, but it is nice to see the ability to match fans with other system components without having to pay the RGB tax. Even so, the fan frame is minimal in design, with only four arms obstructing any sort of airflow. This means a maximum amount of air should flow through the passage without any barriers. On the other hand, the lack of any grille means you should watch your fingers when handling the fan, as they may get nicked in the process. This is especially true as the removable frame slopes inward by design, allowing your little digits to get in the way of the impeller. Embarrassingly, this happened to me several times while working with the Aer F fans.
According to NZXT, there are FDB or fluid dynamic bearings inside the Aer F fans. This patented design is meant to allow oil to circulate around the bearing through grooves, which oil the shaft in a well-greased manner -- pardon the pun. Otherwise, a good bearing means the fans should keep spinning for a long time, while keeping quiet during operation. Interestingly, NZXT states a lifetime of around 60,000 hours or approximately six years. While this is a big number in its own regard, this is still less than half the lifetime of the Cooler Master Silencio FP 120 PWM Performance Edition, and an even smaller fraction of the more recently reviewed Cooler Master MasterFan Pro expected lifetime. I would have liked to see NZXT choose bearings that last longer, though I will reserve my full judgement until the actual performance tests.
Taking a closer look at the fan blades, we can see a few distinct features. As you may have already read, the NZXT Aer F lineup is targeted at creating more airflow, and so certain characteristics can be found. For one, you will see the fins are narrow, with some spacing between the blades. The angles each blade sits in comparison to the rotating middle is quite steep and the blade itself is approximately the same width from the tip to the middle. While the Silencio FP 120 PWM blades were sickle-shaped, the blades found on both the Aer F120 and F140 are quite a bit more flat and blade like, lacking the curvature. Each blade has a cross-section similar to a plane's wing, with a slightly thicker middle and tapered off end to prevent drag. There are a total of nine fins on each NZXT Aer F fan. Otherwise, each blade is smoothed out on the surface; again to reduce any drag the fins may inadvertently create.
As for the frame, you can see each of the corners actually are tapered in. NZXT claims these chamfered edges will allow more air to flow through the intake, boosting overall performance. We will see if this actually plays a role in the overall performance, later in our review. Finally, you might have observed the corner mounting hole has a black rim around it. This is actually a rubber lining to prevent vibrations created between the screw and the fan frame, reducing overall noise created. It would have still been nice to see some padding around the frame, but this should do the job in reducing some vibrations.
This fan, as indicated in its name, is a pulse-width modulation fan, or PWM for short. This means it uses 4-pin headers and connects to most modern motherboards directly. As for rotational speeds, the NXZT Aer F120 and F140 runs from 500 to 1500 RPM. On the topics of sound, airflow, and static pressure, the following lesson on these issues have been borrowed from my colleague Jonathan Kwan's review of the Noctua 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.
With all this out of the way, let us look at the technical detail of the fans. The NZXT Aer F120 is rated at a maximum 57.47 CFM, 32 dB, and 1.03 mmH2O, while the F140 is rated at a maximum 96.26 CFM, 38 dB, and 1.29 mmH2O. By comparison to my last fans I reviewed, the Cooler Master Silencio FP 120 PWM Performance Edition fans produced airflow in between the two units we have today, while generating more air pressure and being quieter than both of the Aer F fans. However, we will see how this actually transfers into our classic performance tests, which looks at more than just the numbers.
1. Introduction, Packaging, Specifications
2. A Closer Look - Hardware
3. Performance Tests