ASUS ROG Strix XF 120 Case Fan Review – Not even bad, but way too expensive

1 - Einführung und technische Daten 2 - Testaufbau, Messkammer und Equipment 3 - Anlaufspannung und Drehzahlen 4 - Volumenstrom (Airflow) 5 - Statischer Druck 6 - Geräuschemission (Lautstärke) 7 - Zusammenfassung und Fazit

Start-up and shut-down voltage

This chapter should be read with caution and attention as long as the fans are not purely analog, i.e. DC-controlled fans with 3-pin connection. The PWM control electronics almost always stand in the way of clean voltage regulation and it is therefore also not advisable to regulate PWM fans via voltage. Nevertheless, we have also carried out this measurement for all models, regardless of whether they are DC or PWM fans, because even strange results say a lot about the control electronics and the use as a DC-controlled fan.

But first, to be on the safe side, we check the maximum speed at 100% PWM and compare it with the datasheet. The fan doesn’t quite manage the specified data, but it is within the tolerance. So that fits already.

In today’s DC test, we see that once the fan has started up, it can handle low voltages starting at around 3 volts, while Noctua’s fan requires at least 4.6 volts. In addition, all PWM fans also only achieve maximum speed and sufficient throughput as well as static pressure under PWM control.

The measured startup values are outstanding, which I would also attribute to the bearing, however, the fan does not really go off, or to be more precise: it already goes off and then below a certain PWM setting also goes on again. We will see the phenomenon in a moment when we look at the curve in the next paragraph.

Start-up and shut-down behaviour

The following measurement curves once again illustrate the very different behaviour. Let’s look at DC control first. Here we do not see any abnormalities yet, even if one misses the specified minimum speed with the simple DC control. This is a feat, because at some point the voltage is no longer sufficient for the motor electronics, which are obviously supplied with 3V.

With the PWM protocol, we can also see very well the distinct start-up pulse, which was set so concisely for safety and which is also pleasing in this form. The rest, as indicated above, then reflects the data from the bar chart. The fan first goes off, then starts up again as the PWM setting decreases, and later goes off again. This is a control electronics problem in this form and should be fixable. The only thing to point out is that it will also be corrected. Peanuts, but still unnecessary.