DeepCool FK120 fan: Efficiency ceiling for some scenarios

Cooling, Extra tests, Fans | | Ľubomír Samák

DeepCool FK120 in detail

It is made in the same injection mould as the FC120, but still has noticeably better properties. Stronger material, higher weight, different bearings and a more powerful motor make the FK120 one of the most attractive options among inexpensive fans. But that’s only assuming the “right” adjustment. Outside of that, this fan can be quite uncomfortable and ironically for the same reason it is sometimes unbeatable.

Never choose a fan based on tests of its other colour variant. The same geometric shapes do not mean that the aerodynamic properties will be the same. These can vary quite significantly – more so than comparing two fans that look nothing alike.

For some fans there may be no difference (as long as the manufacturer took care to achieve the same material strength across colours), for some the differences are quite small (see comparison of a black Corsair AF120 fan with a white one), and in some cases the difference is quite large. Among such cases are the new DeepCool fans, namely the FC120 and FK120. We’ve already tested the FC120 and now we’re adding the FK120 for comparison. At first glance, the only difference between these fans is that the FK120 does not have a light-conducting rotor made of clear PBT (like the FC120). There are however quite a few different elements.

So how is the FK120 different? First of all, it has a rotor made of a noticeably stronger material that resists pressure better (and more force is needed to deform the shape). Lower rigidity is common with ARGB LED fan blades (in this case, the FC120), and DeepCool knows a thing or two about that. In fact, the FK120’s parameters state 19.7% higher static pressure compared to the FC120.

It is true that with the FK120 it is related to a slightly higher speed, but +50 rpm (from 1800 to 1850 rpm) will not make such a big difference in static pressure with otherwise identical fans. Another difference between these fans is that the FK120 has a significantly (45%) more powerful motor, which is useful in overcoming higher resistance environments. The more powerful the motor, the less the fan is typically slowed down by back pressure. The amount of static pressure depends on this as well.

Finally, the FK120 has different, slightly quieter bearings. You can see this in the spectrographs (this is a recording of the FK120 and this of the FC120) when you compare the noise intensity in the 1,5–2,5 kHz band that corresponds to the noise of the bearings and the motor. Based on this analysis, it is evident that different results will be achieved when adjusted to static noise levels. However, the greater rotor strength and quieter bearings of the FK120 do not necessarily mean that the FC120 must always be “worse” at equal noise levels.

   

Different material properties also mean different critical speeds with the occurrence of unpleasant resonant frequencies. And these are one of the main themes of these fans. This is because of the extra-long blades, which even with the FK120 are not strong enough to prevent undulation by torque across the entire speed spectrum. It’s a quid pro quo.

At the expense of everything (even a smaller core), the manufacturer gambled on the largest active cross-section that can be achieved in this 120 mm format. The blade surface area is approximately 12% larger than that of the Noctua NF-A12x25 (PWM). Combined with the pronounced curvature of the leading edges of the blades, the manufacturer has also suppressed the friction and microturbulence that arise on the frame to keep the operation as quiet as possible at high airflow.

It is also worth noting that the weight of the FK120 (170 g) is 27 grams higher than the FC120. The frame is heavier, as it has more filler material on the sides. We can’t note what the difference in weight of the rotors is (their disassembly is only possible in a destructive way and destroying such awesome fans would be a real shame).

* When reading performance values, a certain amount of tolerance must always be taken into account. For maximum speeds, ±10 % is usually quoted, minimum speeds can vary considerably more from piece to piece, sometimes manufacturers will overlap by as much as ±50 %. This must then also be adequately taken into account for air flow, static pressure and noise levels. If only one value is given in a table entry, this means that it always refers to the situation at maximum speed, which is achieved at 12 V or 100 % PWM intensity. The manufacturer does not disclose the lower limit of the performance specifications in its materials in that case. The price in the last column is always approximate.


  •  
  •  
  •  
Continue:
Flattr this!

Related articles

Comments (4) Add comment

  2. Hello
    Your expert explanation helped me make my final choice between the two DeepCool FK120 fans and the ASUS ROG Strix fan XF120.
    The price difference of these two fans in Iran is insignificant and is around 5 dollars.
    Overall, according to your tests, I would choose the Deep Cool fan.
    I hope it is the right choice.

    Your friend from Iran

    Reply

    1. Choosing the most suitable fan for a specific scenario is highly complex. In addition to the fact that all situations in practice are more or less different, each has a different set of priorities of individual characteristics. Someone may prefer lower vibrations to a slightly higher airflow, so that the fan does not end up being a source of excessive secondary noise in interaction with, for example, the case.

      But when you have looked through our tests, taken a look at the context, evaluated the pros and cons, you must have made the right decision. 🙂

      Reply

      1. it would be more complex if we had more high quality fans on the market, but nowadays it’s mostly limited to whether you want maximum performance without noise or maximum performance disregarding the noise
        in the first case you get A12x25 (or T30 if you have space for that), in the other probably some monster from Delta

        if we had high quality fans optimized for specific usecases (like Noctua had in older generations, before releasing the overwhelmingly good A12x25) we could extend that choice to low vs high impedance, but nowadays S12A is entirely irrelevant and their static pressure fans are only used to save money

        Reply

Leave a Reply

Your email address will not be published. Required fields are marked *