Initial warm-up and speed recording
The Silent Wings (Pro) 4 represent the pinnacle of computer fan range. The non-Pro variants stand out especially in system positions and are not well suited for radiators. This is by design and in line with the sort of “micro-segmentation” of BeQuiet. In a white design, like the one tested, it will be quite difficult to find other 140 mm fans that are quieter at comparable airflow.
Initial warm-up…
Before we even start measuring anything, we let the fans run “idle” for a few minutes after plugging them in. This is because immediately after a cold start the fans reach different parameters than after a certain amount of short-term operation.
Until the operating temperature of the lubricant is stabilized, a typically lower maximum performance is achieved. This is because at lower temperatures the lubricant is denser, which is associated with higher friction. Therefore, the fans do not reach maximum speed immediately, but only after the first few seconds. Before the first measurements, we therefore leave the fans running for at least 300 seconds at 12 V, or 100 % PWM intensity.
…and speed recording
The speed of the fans is monitored using a laser tachometer, which reads the number of revolutions from a reflective sticker on the impeller. For this purpose, we use the UNI-T UT372 device, which also allows real-time averaging of samples. Thus, we do not record the peak value in the graphs, but the average speed value from a 30-second time period.
However, the speed itself is a relatively unimportant parameter that is often given more attention than is appropriate. This is the case even in many fan or cooler tests, where speed is used to normalize the different modes in which other variables are measured.
However, hyper-focusing on a specific speed is a rather unfortunate decision if only because the fans don’t gain any commonality. At the same speed all other variables are different, there is no intersection. It can be noted that a better normalization would have been by any other variable, whether it be static pressure, flow or noise level, which wins in our case. But more on that in the next chapter.
We only measure the speed so that you can associate a particular parameter (such as the amount of static pressure or some noise level) with something according to which you can adjust the fan yourself. Perhaps for that alone, the information about the achieved speed is useful. As part of the fan analysis, we will also indicate what the fans’ starting and minimum speeds are. Start-up speeds tend to be higher than minimum speeds because more force is required to get the impeller moving than once the fan impeller is spinning, and a minimum power intensity is sought at which the fan does not stall.
- Contents
- BeQuiet! Silent Wings 4 (BL117) in detail
- Overview of manufacturer specifications
- Basis of the methodology, the wind tunnel
- Mounting and vibration measurement
- Initial warm-up and speed recording
- Base 6 equal noise levels…
- ... and sound color (frequency characteristic)
- Measurement of static pressure…
- … and of airflow
- Everything changes with obstacles
- How we measure power draw and motor power
- Measuring the intensity (and power draw) of lighting
- Results: Speed
- Results: Airlow w/o obstacles
- Results: Airflow through a nylon filter
- Results: Airflow through a plastic filter
- Results: Airflow through a hexagonal grille
- Results: Airflow through a thinner radiator
- Results: Airflow through a thicker radiator
- Results: Static pressure w/o obstacles
- Results: Static pressure through a nylon filter
- Results: Static pressure through a plastic filter
- Results: Static pressure through a hexagonal grille
- Results: Static pressure through a thinner radiator
- Results: Static pressure through a thicker radiator
- Results: Static pressure, efficiency depending on orientation
- Reality vs. specifications
- Results: Frequency response of sound w/o obstacles
- Results: Frequency response of sound with a dust filter
- Results: Frequency response of sound with a hexagonal grille
- Results: Frequency response of sound with a radiator
- Results: Vibration, in total (3D vector length)
- Results: Vibration, X-axis
- Results: Vibration, Y-axis
- Results: Vibration, Z-axis
- Results: Power draw (and motor power)
- Results: Cooling performance per watt, airflow
- Results: Cooling performance per watt, static pressure
- Airflow per euro
- Static pressure per euro
- Results: Lighting – LED luminance and power draw
- Results: LED to motor power draw ratio
- Evaluation
Is the very low speed characteristics similar to that observed in CPS RZ120?
This fan would have been much more competitive if it were to have closed corners by default. The corner swapping gimmick doesn’t seem to offer any actual benefit to me, as the vibrations are already low and similar results in dampening could already be achieved by using rubber mounts. They definitely could have saved some cost and/or priced the fan even more competitively by using integrated, closed corners instead of this gimmicky design.
That said, for users willing to DIY, this should still be a great radiator fan. All you need is some tape to seal up the corners, saving you quite a bit of money.
I mean the F5 R120. Confused with the cooler names.
Yes, if you encounter a lower airflow at the same noise level, a similar characteristic (as with the Silent Wings 4 BL117) is also found in the F5 R120. More fans have this. At such low speeds, the non-aerodynamic sounds must be extremely quiet to leave room to set the speed high enough for leading rankings.
Replacing the corners of the BL117 is really useful if only just to be able to install this fan on a radiator of a liquid cooler, where the SW4 doesn’t make much sense. Although the SW4 doesn’t need to be smeared too much in this scenario. Sure, due to the significant drop in placement compared to other fans, the urge is there, but at higher speeds it even outperforms the NF-A14. Sure, for a fan with modern geometry it’s more of a failure, but…
Using tape to seal the corners is a good DIY “trick”. 🙂
How would you compare it to the Pure Wings 3? This fan seems to constantly get outperformed by its cheaper sibling. The Pure Wings 3 does have a lower RPM limit, but there doesn’t seem to be other major disadvantages by going for the Pure Wings instead.
Now I’m really curious how the high speed, 9-blade version of the Pure Wings 3 performs.
The 140 mm Pure Wings 3 with 7 blades often seems to be a balanced (and a hair more more efficient) solution like the Silent Wings 4 (BL117). Although we have the SW4 in the white variant, which probably tends to be a bit noisier. These small differences (in tonal peaks) do not show up on radiators, where the tested PW3 variant has a significant advantage for obvious reasons (good sealing corners). We are also curious about the 9-blade Pure Wings 3 in 140 mm format. We will probably get to it after the announced Arctic P14 triple fan test (PWM PST, PWM PST CO and Max). 🙂
The Pure Wings 3 has a MTBF of 60 000 hours, which can be a disadvantage compared to Silent Wings 4 (with 300 000 hours). Lower robustness of critical parts in terms of durability (or change of properties over time) can also be indicated by the smaller impeller hub (of the PW3 BL108) and also at higher speeds relatively higher vibrations (again of the PW3 BL108), which could also indicate higher manufacturing tolerances. Of course, these vibrations could also be due to vibrations on the blades, but I assume they will be composed of several sources. And one of them will be related to the quality level of the impeller centering.
I guess the P14 trilogy will be consecutive releases then.
It’s a shame that we can’t have a Silent Wings 4 that comes with sealed corners, otherwise we’d have a reliable (and strong performing) 14 cm fan in the ~20$/£ price range that would compete very favourably vs. the Noctua A14 for example. I guess that’s done to prevent cannibalising their sales of their own flagship, but I’m not sure if it’s a smart move given the tough competition…
Yes, the next test will be the P14 PWM PST CO and I will conclude the trilogy (on Monday?) with the Max model.