Here follows non technical and subjective information:1. A little about my current setup
Since it's a PWM fan, I decided to connect my ZALMAN CPU cooler to a conventional 3-pin case fan connector on the motherboard and have the Nexus PWM fan connect to the CPU fan connection for full PWM functionality. My ATX case, the Super Flower SF-201T3-BK, has a total of five places for fans (all 80mm; two in front, two in back and a single one exactly in the middle of the top panel). The Nexus PWM is mounted in the top to help exhausting air along with the PSU fan.
2. Noise?
(ASUS P5K WS motherboard). In the BIOS, I have set the ASUS Q-Fan feature to enabled for the CPU fan. I also set the CPU fan type to PWM and the fan profile to Silent. The Nexus PWM fan operates at roughly 1200RPM with the Silent profile, around 1500RPM with Optimal and 2000RPM with Performance profiles. In Silent mode the fan actually is quite quiet. I can't say it is silent. My PSU has a much more quieter fan (some ADDA fan, it's the Nexus NX-8040) so maybe the experts can make a good guess in dBA on how noisy the Nexus is at 1200RPM. When using Optimal profile, the fan is VERY audible. It makes a lot of noise and the difference is only a pitiful 300RPM! In Performance mode... CHEESH! Even my DVD drive spinning a DVD at 20x speed sounds quieter!!!
3. Vibration?
The Nexus came with silicone fan mounts. And that for a good reason. The fan VIBRATES like hell! Do you know these devices which massage your back or those small pool like things were you put your feet in warm water which get massaged with mega vibration? This fan vibrates just as much! It is a requirement to use the silicone fan mounts or else your PC will vibrate like a monster and make more useless sounds!
4. How much air will it push in or out?
With Silent profile it rotates at 1200RPM, so it should move a little air. Notice that the maximum airflow in CFM is noted at Nexus' website. I don't have any meters or know the calculations to give you any CFM numbers, but by placing my hand on the fan (the air is coming up facing my hand), I feel very little air that comes out.
5. Is it a good buy?
Stay away. The Nexus Basic 80mm case fan is much better, can rotate at higher RPM than the PWM while still making less noise and of course pushing much more air than the PWM one (also the Basic vibrate sMUCH less than the PWM!). One thing that is very annoying about PWM fans is that they spin up ultra fast when booting up your system and then slowly go down in speed. It makes you get disturbed or at least it made me get disturbed every time I powered on the PC.
6. Whining?
Many users have reported that PWM fans suffer from whining. The Nexus PWM does whine a bit, but only a bit. It is noticeable only when being very near to the fan, but at 20-30cm away from the fan the whine is not that noticeable, but it is there.
7. So after all this nonsense what do you say about PWM fans?
They are becoming increasingly popular, but with most motherboards limited to a single PWM connection and the fact that (at least the Nexus) PWM fans make whine and more vibration than their "normal" DC counterparts, I doubt any silent computing enthusiast will buy a PWM fan. I say it straight: they suck. Who cares if the fan is auto controlled? Just move your ass and go buy a fan controller then hook up your case fans to the controller and put the speed manually up and down. Of course if you're like me and hate dangling cables then you might as well buy 3-pin to 3-pin voltage reducing adapters like ZALMAN RC-100 which makes 12V to approx. 5.5V (In combination with my ZALMAN CNPS-7000C CPU cooler, the fan on the ZALMAN spins at around 1000RPM and is NEAR INAUDIBLE level! And the CPU still is cool at around 38C when idling!)