The design details here not only look fascinating, they really are. That is, except for one “little thing” that makes the MagFlow 1225 PWM unable to play an equal game with the top 120mm fans, even though it seemingly has all the prerequisites to do so. But at least the Seasonic fan has the added value of a very convenient installation: magnet here, magnet there, no cables in sight.
… and airflow
With airflow measurements, we can well explain why the test tunnel is shaped the way it is. It doesn’t consist of two parts just so that the “exhaust” can be conveniently clogged for pressure measurements. The anemometer (i.e. the wind speed measuring instrument) is held together by two parts, two formations, through the flanges.
The front part, at the beginning of which the fan is mounted, becomes steadily narrower and from about two thirds of the way through the cross-section is smaller than that of a 120 mm fan. The reason for this is that the cross-section of the anemometer is always smaller than that of the fans tested. The taper towards the anemometer fan is as smooth as could be chosen and the tunnel walls are smooth. This has minimized the occurrence of unnatural turbulence.
The difference between the cross section at the intake (fan under test) and at the constriction point (anemometer) also means a difference in dynamic pressure, the principles of the Venturi effect apply here. In order to avoid distortion at this level and to ensure that the fan airflow is not different from what it actually is, the Bernoulli equation must be applied to the measured values (for maximum accuracy, the calculation also takes into account the internal cross-sectional area of the anemometer, i.e. its inactive part ). After all this, it is again possible to confront our results with the paper parameters.
We use an Extech AN300 anemometer with a large 100 mm fan for the measurements. Its big advantage over other anemometers is that it is made for bidirectional sensing. This allows tests at different fan orientations. However, the “pull” position is more suitable or accurate for measurements, even though it may not seem so at first glance, but we’ll explain.
Here, we get to the second part of the tunnel, the part behind the anemometer. It is part of the whole device, mainly to allow a laminar flow of air to arrive at the rotor of the anemometer. Otherwise, uncontrolled side whirls would be reflected in the results, which are inconsistent with accurate measurements. Therefore, we will test the flow in the pull position. If anyone would like us to elaborate more on this topic, we can elaborate further at any time in the discussion below the article. Ask away. 🙂
In regard to the anemometer, we shall return for a bit to noise measurements and to setting modes according to fixed noise levels. It may have occurred to you as you were reading that the anemometer fan is also a source of sound that needs to be filtered out when measuring fans. For this reason, we insert a securing pad between the frame and the anemometer fan before each measurement and mode setting according to the fixed noise level. This, by the way, also holds the anemometer fan during static pressure measurements.
It’s surprising to me that, despite having a small impeller and relatively large gaps between the blades and the frame, the fan doesn’t perform too badly. The large blade surface area likely helped. The performance relative to the price is really bad though…
The price is likely high due to both the LCP blades and fancy magnetic connections. The later of which seemed executed well, but the former is “wasted” due to Seasonic not using this advantage to make the gaps smaller. With the current impeller design, they might have been able to use reinforced PBT with little penalty while significantly lower the cost. Really puzzling why they go LCP without fully taking advantage of it.
I also wonder if the magnets are what leading to the frames being so thick. The diameter of the impeller is noticeably smaller than many other 120 mm fans, which is something commonly seen in other fans with similar magnetic connections. It is in my opinion a bad tradeoff.
Despite all its flaws, it’s a decent first fan from Seasonic. Hope they can fix the motor issue and improve the fan in other ways in their next iteration.
Very good point, about the smaller rotor of the MagFlow fan. But it is still significantly larger than on the Arctic BioniX P120 A-RGB. There is some compensation in the smaller area of the hub, but it is true that the efficiency is much lower in these places than at the other end of the blades.
It is also true that smaller gaps between the blades may not be such an advantage compared to traditional 7-blade fans, when you take into account that with a larger number of blades there are also larger gaps and the total area is decisive. Although it always depends on the geometry and inclination of the blades themselves. The number and length of the leading edges also play a role in the overall efficiency or airflow/noise ratio, so more blades may not always be a plus. Arctic probably knew very well that with fewer and larger blades, a lower noise level could be achieved at the same airflow. I mean, under certain circumstances, theoretically, when the noise level is not increased by the tonal peaks from vibration, that is… they figured that out later.
With a quieter motor, the MagFlow fan would show up in a completely different light, although it would probably not reach the peak at any of the noise levels. But we know that this geometry makes sense. Although less so in the high-end than in the low-end. It wasn’t that long ago that we were dealing with Genesis Oxal fans, whose basic outlines are similar to those of the MagFlow fan. Unfortunately, we don’t have its results publicly (it was an internal prototype test), but when Oxal fans come out (for now they can be bought only as part of cases) and we add them to the tests, you will see how they shuffle with the class of the cheapest fans. There the price/performance ratio will be a bit different… 🙂
MagFlow 1225 has very well-made appearance and decent ~ middle efficiency for some obstacles but.. the problem is that the price is as expensive as other high-end fans. I also found the same cons of MagFlow as your test.
In my test, Magflow shows especially worse result in radiator-pull test.
Some PSU manufacturers started to make their own PC cooling solution recently. And Seasonic’s product, which was the first runner among them, seems to fail in the competition. I would like to see if Super Flower’s Megacool can show good result. Challenges of various companies for PC cooling solutions makes the topic about it more interesting, isn’t it?
Thanks for the heads up about the Super Flower Megacool. I didn’t know about this fan and yet it looks like a capable challenger to the T30. Although personally I think one of the benefits of Phanteks is the smaller number of blades, which under certain circumstances (when there are no tonal peaks due to excessive vibration) can achieve higher airflow and static pressure at lower noise levels… by having fewer edges cutting the air. Arctic also seems to have worked with this thesis already with 5-blade designs. Though initially they underestimated the choice of material, or the need to reinforce the blades with a rotor frame, which was added later.
Heavily curved 9 blades, LCP impeller, 30T thickness. But not only that, Megacool has quite interesting feature.
https://img2.quasarzone.com/editor/2023/07/12/deac9fde48ba4aceebed595f2d8a9281.jpg
It has 12 pole motor! I never have seen this before in PC fans.
But one concern is that it uses 2 ball bearing. Megacool can have irritating noises. I can’t predict whether or not Megacool have tonal peaks due to aerodynamic interaction, but the bearing driving noise will seem clear to hear..
So even assuming there is no tonal peaks from Megacool, the lower normalized noise level of each fans, I think PH-F120T30 will make the better airflow/static pressure.
The Megacool also kinda sucks for its price,
Bearing noise isn’t even its problem, its the poor dynamic balance and motor noise. It especially makes funny motor whines when stopping at low speed or when it starts spinning. But it also makes weird noises when accelerating
But however, what is actually interesting is they for whatever reason, included a remote control to control fan speed profile