Dynamic X2 GP-12 PWM: Fractal Design knows what works in cases

Evaluation

Sometimes they don’t even get a chance and are immediately replaced by other, “better” ones. We’re talking about fans that come pre-installed in computer cases. We are going to test one of them now and although there are reasons to replace the Dynamic X2 GP-12 (PWM), be careful not to end up being worse off. After all, these aren’t exactly ordinary fans. They even have more specific aerodynamics and acoustics modifying features.

Evaluation

In an environment without any obstacles (filters, grilles, radiators, …), the Dynamic X2 GP-12 PWM results are slightly below average. At low noise levels, also because of some whirring. Because of it, it was not possible to slow the fan down to the quietest test mode at 31 dBA on obstacles.

But the airflow through a nylon filter is decent, at higher speeds (where the whirring is already overcome by stronger “aerodynamic” sound frequencies) it even outperforms the Noctua NF-P12 redux-1700 PWM. What is remarkable in the faster modes (with turbulence amplification) is that the noise level with the nylon filter is lower than without it. This is due to the laminarization of the air, which occurs partly at the filter level. We have already noticed this with some other fans, but here the phenomenon is the most pronounced. We didn’t measure higher noise levels even on a thinner finned radiator (FPI 15). The effect of mechanical resistance is thus clearly smaller than the nature of the airflow in terms of overall noise. This is just a curiosity, in the vast majority of cases obstacles more or less increase the noise level.

The Dynamic X2 GP-12 PWM performs above average on a hexagonal grille. It may not be enough for the SilentiumPC Fluctus 120 PWM, but it outperforms the BeQuiet! Pure Wings 2 with ease. However, it is important to add under what circumstances. The resulting sound no longer contains only whirrs (which in spectrographs are peaks at 1.6 kHz), but also amplified frequencies around 320 Hz. These are characterized by the generation of “huuu”. The Noctua P12 (redux) also behaves similarly on the grille, by the way, with a very similar blade shape in principle.

As this is a fan with a claimed high static pressure, and this is indeed achieved (as opposed to the claimed airflow), it is worth paying attention to the operation on a radiator. Results in normalised modes by noise level are average to below average compared to other fans. Again, without the presence of the mechanical motor sound, the Dynamic X2 GP-12 PWM would have ranked better, especially in quieter modes.

The whirring has been mentioned so many times that you might get the impression that it is something unbearable. It isn’t. I mean, it depends for whom. The Cooler Master SickleFlow’s whirr is much more intense, and the SilentiumPC Sigma Pro 120 PWM fan is significantly more annoying in this regard. For regular users, the sound of the Dynamic X2 GP-12 PWM will not be a reason to remove it from the case and replace it with another fan. In a closed case about a meter away from the head this sound is lost and only the demanding and somewhat hypersensitive users will have complaints.

The surprise of the evening is the very low vibrations. After the Xigmatek XLF-F1256 and the BeQuiet! Pure Wings 2 (BL039) this is the third time that we observe such a pleasant behaviour in a fan with rifle bearings. The principle of operation is basically the same as with conventional plain bearings, but in the “rifle” type there is apparently considerably less friction.This is also indicated by the low operating power draw. This is probably why manufacturers can afford to write two to three times the mean time between failures compared to conventional plain bearings.

Lower friction means less wear and naturally longer life. But Fractal Design also states in its materials the use of a balance magnet, which reduces axial stress. Either way, the Dynamic X2 GP-12 PWM won’t make your case ring, even if it’s made of very thin sheet metal. So the title of the article mainly refers to this fact and it is not a bad fan in terms of performance either. It won’t please everyone with its sound, but most users won’t complain. However, it should also be noted that buying the Dynamic X2 GP-12 PWM purposely (separately) doesn’t make much sense. The airflow per euro is average across the board at all noise levels, and there are more efficient fans available. Even within the higher end models from Fractal Design, which we’ll gradually work our way up to.

English translation and edit by Jozef Dudáš

• Contents
• Fractal Design Dynamic X2 GP-12 PWM in detail
• The basis of the methodology, the wind tunnel
• Mounting and vibration measurement
• Initial warm-up and speed recording
• Base 7 equal noise levels…
• .. and sound color (frequency characteristic)
• Static pressure measurement…
• … and 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 by 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