Page 2 - Physical Look - Hardware
Fans are often seen as an add-on to your build and deemed more to be a functional item rather than for design or appearance. As such, the Cooler Master SickleFlow 120 fans are not too showy in their aesthetics. Each utilize a black plastic frame, while the impeller is of a different color plastic depending on the model. The standard SickleFlow 120 is a very dark grey that is still translucent if you look closely. The models with LEDs inside are made of a translucent white plastic. Cooler Master does keep their logo in the middle of the fan with a large silver sticker and the Cooler Master hexagonal logo outline. On the edges, you can see there are black rubber pads around each mounting hole. These act as dampeners for the fan, reducing vibration and the resultant noise that the fan may make when mounted onto something stiffer.
Internally, the fan utilizes rifle bearings. These bearings are similar to sleeve bearings in the sense they have a lubricant inside the bearing to keep operation smooth and friction at a minimum. However, they have been modified to operate at a lower noise and a longer lifespan compared to traditional sleeve bearings. In addition, Cooler Master has mentioned they have improved the bearing sealant to reduce the likelihood of leaking while also possessing a MTTF of 160,000 hours, which translates into over eighteen years. We will see what the noise output is like when we test these fans later.
Taking a better look at the fan blade, you can see some notable features here. The fins are a bit narrower than some other fan blades with a more angled slope near the tip. There is a gap in between each fin with no overlap. The angle each blade sits in comparison to the rotating middle is close to 45 degrees. The overall blade is shaped a bit like a sickle, hence the name, with quite a bit of curvature. There is a total of seven blades on the impeller. Otherwise, each blade is smooth without any dimples or abnormalities.
On the output side, four arms hold the fan and obstruct air from passing through, which means we should have a near maximum amount of air flowing through the passage. On the other hand, you should be careful that your fingers do not get in the way of a moving impeller, especially with the lack of any grille here. 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, which 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 do 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 all the time.
With regards to the application and CFM, it is generally optimal to have a fan to have a high air volume flow rate. However, 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 need less static pressure and faster airflow. There are times where case fans will require higher static pressure too, such as the front 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 Cooler Master SickleFlow 120 fans spin at a maximum 1800RPM and is rated at a maximum 62 CFM, 27 dB, and 2.5 mmH2O. From these numbers, these fans offer a good balance between airflow and air pressure. As such, the SickleFlow 120 fans could be used for either for case fans or for denser applications, like heatsinks or radiators. In fact, these are the same fans we found included with the MasterLiquid ML240L V2 RGB all-in-one cooler. We will see how this actually transfers into our classic performance tests, which looks at more than just the numbers.
For the vanilla Cooler Master SickleFlow 120 and SickleFlow 120 Red, we have a single cable with a 4-pin PWM controlled fan header at the end. This measures to just over 300mm in length. This is actually a bit shorter than I would expect, as we have seen fans come with at least double the length. For the RGB and Addressable RGB models, we have a second cable that also measures the same length with the respective headers to control the lighting. As expected, the SickleFlow 120 RGB has a standard four-pin 12V header, while the SickleFlow 120 ARGB uses a standard three-pin 5V header. These headers are made to be compatible with major motherboard manufacturers like ASUS, ASRock, and MSI. This extra cable also has a second plug that is attached so that you can daisy chain multiple lighting products. Just be sure to not mix the RGB or ARGB headers together, because they are not cross-compatible. Both of the cables are black in color and have a braided sleeve around it for added durability.
1. Introduction, Packaging, Specifications
2. Physical Look - Hardware
3. Performance Tests