Conclusion
Same model, different pieces. Differences in vibrations can be dramatic. Especially if they are cheap fans with high manufacturing tolerances. While most Endorfy Stratus 120 PWM fans have some vibration, you can also come across “golden” samples that don’t vibrate at all. This is admittedly a very rare but existing situation. The variance of vibration is much greater than you might think.
Conclusion
The differences in vibrations across different pieces of Endorfy Stratus 120 PWM fans can be diametrical. Basically from no vibration on the frame to higher vibration, but never downright high. If you go through the database of vibration results of other fan models, you’ll find that even the Stratus 120 PWM sample (6) with the most intense vibration still fares better than the Arctic BioniX 120 A-RGB or the Cooler Master Mobius 120 OC, which even has a hoop to damp vibrations caused by overly flexible blades. So why does it vibrate significantly? Because the vibration is caused by a different reason than on the Stratus 120 PWM.
We’ve discussed a number of causes for fan vibration in this article, and in the case of the cheap Endorfy fan in particular it seems to be poorer rotor centering. Or rather, depending on the sample. The variance in the widest band, at 1400 rpm, is 0.00–0.263 mm/s. Some samples achieve relatively worse results even at lower 1200 rpm. We assume that the main source of Stratus 120 PWM vibrations is the varying precision of rotor mounting, which is also affected to a large extent by the quality characteristics of the axle. It is probably the quality characteristics of the latter that determines most whether a particular piece vibrates more or less than another. It depends on the accuracy of its position on the center, but also on whether or not it is perfectly straight.
If you visually compare the piece with the lowest vibration (sample 3) and the highest (sample 6) you will find nothing to suggest that each fan vibrates slightly differently. The weight is the same and the build quality is no different either. The edges of the blades are also nicely smooth. In short, on the outside one appears exactly like the other and the quality differences are hidden on the inside.
The vibrations from the undulations at the end of the blades obviously don’t transfer much to the frame. If this were the case, it would not happen that we measure 0.00 mm/s on one sample (3). Nevertheless, some vibration does occur at the blades. Too weak to reach the frame, but at the same time of a frequency sufficient to produce tonal peaks at low frequencies of sound. These are comparable for all fans, regardless of whether it is the piece with the lowest or highest vibrations.
Of course, pieces with higher vibrations may have a significantly different sound, but this will already vary from use case to use case. It depends on how the fan vibration on the frame will react in combination with the particular case or cooler they are mounted on. While in one environment they may get into resonant frequencies with annoying tonal peaks, in another they may not. You can’t really deduce the intensity of vibration without using a vibrometer, only based on frequency analysis of the sound, although you may come across such hypotheses in the public space. A noisier fan, with higher tonal peaks, may well have lower vibrations (even if they are purely blade-level vibrations) than a quieter fan that vibrates more, but outside the most critical resonant frequencies. We’ll cover this in more detail, it would be a bit off topic now.
So yes, with cheap fan models it makes sense to rummage through a little, qualitatively you can come across different pieces. Later on, we’ll repeat similar tests with more expensive fans with more robust axles and you’ll see that there will already be significantly smaller differences between them. We already know this based on the fact that with all the fans we test, we rely on multiple samples. And high-end models such as the Noctua NF-A12x25 (PWM), the Phanteks T30 or the BeQuiet! Silent Wings (Pro) 4 do not differ much in this respect and scale very well with each other.
English translation and edit by Jozef Dudáš
- Contents
- Each piece has different vibrations
- Results: Vibration, in total (3D vector length)
- Results: Vibration, X-axis
- Results: Vibration, Y-axis
- Results: Vibration, Z-axis
- Conclusion
The tolerances in cheap GPU fans are even more liberal. This month I returned 2 GPUs. Asus Dual had one utterly defective fan motor, easily +10dB more than the other fan. MSI Gaming X had one of the fans slightly louder. However, slightly louder at the ridiculous minimum of 1000 RPM means LOUD!
You have opened a very good topic. The disproportion of users who think about different coil whines and those who think about various aerodynamic noises is at least remarkable. Especially considering that not only on the basis of these public tests I know that the difference in coil noise between pieces of graphics cards of the same model is usually negligible, or below the level of what a person can recognize. Of course, that’s in cases where equal models means equal VRM design with equal components. If the VRM design is different and based on different components, then yes, there can be a significant difference in noise level, but this is a very rare case.
Much more often, as you write, is that the fans behave differently at the same load. This is probably due to several reasons. The difference in efficiency of the heat transfer from the chip to the cooler probably has some influence on this, which can be caused by even such a small thing as the different application of thermal paste. But one of the main reasons, I think, will be the different quality of the PWM signal. It can be interpreted differently by each cooler and sometimes quite incorrectly. This is evidenced by cases where some graphics cards increase the fan speed even though there is no reason to do so, because the higher speeds are achieved by jumps even with low temperature. This is probably due to a misreading of the PWM signal. And it can probably also be set in a “stable” way, where one sample of the same graphics card model always has slightly higher speeds than another one.
This is one of the topics that we hope to be able to discuss properly. I even have already noted how the methodology should look like to be satisfied with the result. And the time commitment is really extreme. Space for that is quite hard to find. If someone beats us to it and handles these tests with precision and responsibility, I won’t be angry at all. 🙂
Deshrouding seems to be the most reliable way to silence a card (aside from coil whine). Few reviews actually analyze the cards at low noise levels.
Get a card with easily removable fan/shroud and a flat heatsink (preferably one using heatpipes and fin stacks instead of extruded aluminium), then mount standard fans on it using case mounts/zipties/heat resistant double-sided tape. Plug the fans to a motherboard fan header and use Fan Control to control them. Fans of different sizes and thicknesses can be chosen to fit the particular card and case.
Exactly, I think that deshrouding and 2 good 120mm fans are the only way to achieve GPU silence. 4-pin to 4-pin VGA adapter and Y splitter let the fans be completely integrated with the GPU but the minimum at 30% fan’s max RPM is still a limitation for Nvidia, so something like Noctua A12x25 LS with 1200 RPM max would be perfect.
The most difficult thing is creating at least something partially working as a shroud for the new fans, otherwise, the air flow and thermals will be quite bad.