Okay, I didn't take any pics, but there's an abundance of them on the net, which I will reuse.

Introducing, the Arctic Fan 12.
Pic 1, anterior-posterior view (which means from side, when laid down)
Pic 2, superior-inferior view (top down, when laid down).

As you can see from pic1, the Arctic Fan 12 isn't your ordinary fan. The fan is held onto the frame via rubber, which in theory will reduce fan noise. "Arctic Cooling have achieved this through the use of their new sound/shock-absorbing mechanism in conjunction with a special frame that allows the unit to suck air from the sides as well as the front." Impressive.

Bear in mind that the wires are sleeved in black. It looks really slick, with a rubbery texture.

Here's its specifications:

* Dimensions: 120 x 120 x 38.5mm
* Bearing: Fluid Dynamic Bearing
* Fan speed: 400 - 1500 RPM
* Air Flow: 56.3 CFM / 94.7 m3/h
* Power consumption: 12V, 0.13 Amp
* Noise Level: 10 dB(A) - 23.5 dB(A)
* Price Paid: AUD$17.50


Very nice specs, 23.5dB is quite inaudible.

Introducing the S-Flex.
pic1, top down view.

Only one view, it looks exactly like another 120mm fan. Nothing really fancy. comes in a box with a nice diagram on how the fan keeps quiet. Unlike the Arctic Fan, this fan isn't sleeved.

Here's the specifications:

Model Number: S-FLEX SFF21E (1200rpm)
Dimensions: 120 x 120 x 25mm
Specifications: 1200rpm Version: 49.0CFM / 20.1dBA / DC12V / 0.15A
Connector: 3-pin (4-pin adaptor included)
Cable Length: 30cm
Bearing Type: S-FDB (Fluid Dynamic Bearing by SONY Corporation)
MTBF: 150 000 hours
Price Paid: AUD$29.95

This fan has a lower CFM, with lower noise levels to boot. Interestingly enough, it draws more power, 16.67% more in fact.

My thoughts:
First, I am NOT a professional reviewer, and I'm doing this on my own time for free. I got these items at my own expense, for my own use.

Second, I have written this review for those out there where noise is the main concern, performance a close second, and price if of no object.

And before I continue, I would like to point out some simple high school physics. dB is a unit that is NOT linear. In other words, having double the amount of dB DOES NOT MEAN double the amount of noise.

In fact, a 3dB increase signifies double the noise. This means that the Arctic Fan 12 is actually more than DOUBLE the S-Flex's noise levels, according to the specs.

This difference in noise levels are actually VERY apparent. At the moment, my computer is configured to have an Arctic fan as exhaust permanently at max speed. A second Arctic fan is used on the CPU (now referred to as Arctic2), which was then replaced by the S-Flex (now referred to as s-Flex). The methodology isn't the best for determining which fan performs better, but that is not the main point of this review.

My results were simple. I will use a scale of 1-10, where 1 is absolutely no sound whatsoever, and 10 is the sound produced by a HDD starting up (which is relatively quiet). I reckon a 6-7 or below would make the PC inaudible enough to sleep with. Stock Antec Sonata II case would rate a 4-5.

Lets assume that with NO FANS on, the noise produced by this computer is a 1-2. Almost completely inaudible, with only my Antec TP3 650W PSU 120mmfan the only fan running. The HDDs and optical drives have stopped spinning. Motherboard/graphics card has absolutely no fans. For the purpose of this testing, I have rigged the CPU fan to a switch: instant on and off.

When the Arctic2 was used, the noise levels were very quiet. These noise levels are at the scale of 3-4, which makes it quieter than an Antec Sonata II case with stock fans. They are still audible with the computer next to my feet, although a very slight, mid-low pitched sound. The noise levels went down a little when the Arctic2 was switched off.

With the S-Flex, these noise levels were down to a 2-3. It is a very apparent change. The quality of the sound is exactly the same, mid-low pitched sound. However, my surprise came when I shut off the S-Flex, and kept the exhaust fan on: there is ABSOLUTELY NO CHANGE in the amount of noise I can hear. I cannot say if it sounds exactly the same as the Arctic2 switched off, as I cannot compare them side by side, but it does sound the same.

I decided to try something else: I unplugged the exhaust and GPU fan, and did the same test.

The Arctic2 sounds like a tornado compared to the S-Flex.

With some temperature testing, the 7cfm did not register much of a change to CPU temp. I registered a 1C increase in temperature. I will leave this to you to decide if it was important.

With these results, I would love to say that the S-Flex would be my choice of a fan anyday. But bear in mind that this simple test is far from scientific, but I demand the very quietest in my computer as it runs 24/7 about 1m from my bed.... I have lived with the Arctic Fans being the only fans in my computer for about 2 weeks, and they really are inaudible enough to sleep with, easily. However, nothing beats the absolute silence offered by the S-Flex, which leaves me with an extra Arctic Fan 12 lying around gathering dust.

Also bear in mind that the S-Flex costs almost double what the Arctic Fan 12 costs.

Summary
Pros Arctic Fan 12: Sleeved, quite inaudible, decent cfm, cheap(er).
Pros S-Flex: to the point of absolute silence.

This review has come to a twisting conclusion. I welcome any feedback.