Scythe Kaze Flex II 120 Slim: Well balanced SFF fan

Measuring the intensity (and power draw) of lighting

Low-profile fans are a special category, but sometimes they are unavoidable in more confined spaces. For technical reasons, it’s always about compromises compared to more respectable fans of normal thickness, but their weight can vary. If the Arctic P12 Slim and Alphacool SL-15 don’t fit your needs, the Scythe Kaze Flex II 120 Slim may be the closest thing to what you’re looking for.

Measuring the intensity (and power draw) of lighting

Modern fans often include lighting. This is no longer a “cooling” parameter, but for some users the presence of (A)RGB LEDs is important. Therefore, we also measure how intense this lighting is in our tests. These tests are the only ones that take place externally, outside the wind tunnel.

We record the luminosity of the fans in a chamber with reflective walls. This internal arrangement is important to increase the resolution for us to measure anything at all with lower luminosity fans. But also so that the readings do not blend together and it is obvious which fan is emitting more light and which one less.

Fan in the light chamber to measure the intensity of (A)RGB LEDs

The illumination intensity is measured in the horizontal position of the fan, above which is the lux meter sensor (UNI-T UT383S). This is centered on the illumination intensity sensing chamber.

The illumination is controlled via an IR controller and the hue is set to RGB level 255, 255, 255 (white). We record the brightness at maximum and minimum intensity. According to this, you can easily see if the brightness is high enough, but conversely also if the lower level is low enough for you.

In addition to the brightness intensity, we also measure the power draw that it requires. This is again through the shunt, which is between the Gophert CPS-3205 power supply and the (A)RGB LED driver. After this we get a reading of the lighting power draw. In the graphs we show it separately, but also in sum with the motor power draw as the total maximum fan power.


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Comments (5) Add comment

  1. On the evaluation page, the link to frequency analysis on plastic filters was wrong (39 instead of 29). Also, the summary was wrongly replaced by the spec table.

    On your evaluation of frequency, you say thay the weakness of the fan only shows when it runs above 1100 RPM (that is 45 dBA). But from reading the charts, there seems to be strong peaks that appear in 39 dBA mode (959 RPM) as well. Did I interpret the data incorrectly?

    1. Thank you for the heads up. Corrected. Including the charts that were really messed up. I was already in advanced stages of exhaustion when I released it yesterday…

      … you read the spectrographs well. Yes, you are right, even the 39 dBA (~959 rpm) mode is characterized by more pronounced tonal peaks, so I’ve modified that statement a bit. Below 850 rpm it’s fine in that respect. Approximately such speeds at 39 dBA correspond to tests with a plastic filter and on a grille, which increase the noise level, so when tuned to the same level the fan speeds will always be a bit slower than in a use case without an obstacle.

      So thanks for this observation and apologies for the inaccurate interpretation of the results. I wrote the article a bit under pressure and at the same time on the verge of complete exhaustion. I hope that similar mistakes will be avoided in the future.

      1. You don’t have to apologize, it does not take away from the fact that the overall analysis is great work.

        Health is very important. I hope you’ll find time to take a good rest and don’t push yourself too hard 🙂. Take care.

  2. Guys, please test 120 and 140x25mm Kaze Flex – they were highly praised by other (but not as advanced as you) reviewiers, especially as case fans. I generally really like them from my own experience for being solid performers; sounding well; having quiet motor and bearing and representing nice quality additionally proven by few years of using them in my own pc.

    1. Sure, the 120 and 140 mm Kaze Flex II will be next in line as far as Scythe fans are concerned. I mean, maybe the Grand Tornado model, which is close to release, will fit in between them.

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