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Noctua Tease Their Impending Sterrox-Made, A-Series, NF-A12x25 Fan

Mar 13, 2018
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Ever felt like spending more money on fans then your hole pc ?
By my calculations for the current NF-F12 which is around 22$ , 4x the martial cost that would be around 88$, lets slap the premium name on top of that 88+Noctua = 99.99$
Not 4x retail, but 4x material cost so probably 25% direct increase. Now, factor in one less fan, marketing and design recoupment, I'd say more like 2x to 2.5x.
Oct 5, 2017
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Also that shows those very hard "steps" of Noctua's bearing/motor stopping fan fast.
It's like it has some angular axle.
That's no good at all for getting smooth low vibration rotating.
What you're talking about is nothing to do with the bearing and they're not "steps" whatsoever.

It's the use of a 4 pole motor. You're right that using more poles can reduce vibration, but it's not because 4 pole motors are inherently bad. It's to do with the switching of the poles as the motor spins.

To reduce vibration and make rotation as consistent as possible, you can either switch the poles at the appropriate, accurate point in the rotation to drive the fan (Thus meaning the motor can apply the same level of torque at all times, rather than having to spin the fan fractionally back up to speed each time the pole switches), or you can use more poles so that the accuracy of the switching can be reduced. Neither approach is better - the more poles approach is easier to design but has a higher material cost, the traditional 4 pole approach CAN introduce vibration (because the torque of the motor must be applied very precisely), but it's real drawback is that the manufacturing tolerances must be better if you intend to avoid vibration - both approaches can and do, produce fans with no vibration issues at all - the 4 pole approach is by far the more common however, and the gentle typhoons, scythes old s-flex series, and almost any other case fan you've ever owned is probably a 4 pole. Proof in relation to the GT is right here - http://thermalbench.com/2017/05/25/darkside-gentle-typhoon-1150-rpm-120-mm-fan/2/

The only 6 pole motors I know of are the ones in be quiet's silent wings fans.

The reason the noctua shown here seems to have more distinct behaviour as it comes to a stop is because it only just barely rotates over the magnetic pole at the last moment, whereas the other fans in the lineup came to a stop in between magnetic poles in the motor. Run the same test a bunch of times and you'd see the noctua's rotation look like the other fans the majority of the time.

The reason the noctua slowed faster is also obvious, and not at all related to the quality of the design or product - it simply has a great deal more mass at the tips of the blades due to the extreme sweep of them and the very shallow rake, whereas the noctua is an S12, which has almost no sweep and a very steep rake, thus most of it's mass is in the center and it also presents a flatter profile to the air which will also reduce it's ability to keep spinning. An A12, or F12, would have spun a great deal longer.
Last edited:
Oct 31, 2008
1,023 (0.30/day)
Portland, OR
Processor AMD FX-8350
Motherboard Asus M5A99X Evo
Cooling Noctua
Memory 16GB G.SKILL Sniper DDR3 1866
Video Card(s) EVGA 980ti FTW
Storage (OS)Samsung 950 Pro (512GB), (Data) WD Reds
Display(s) 24" Dell UltraSharp U2412M
Case Fractal Design Define R4
Audio Device(s) Sennheiser GAME ONE
Power Supply Corsair HX750i
Mouse Mionix Castor
Keyboard Deck Hassium Pro
Software Windows 7 Pro x64
This is great news being that I only buy Noctua. Unfortunately, I'll have to wait until they come out with these in 140mm.

I'm fine with the colors; I don't ever use windowed cases or RGB bling with the only exception being my keyboard.