The F12 Pro PWM comes in a fan-sized box containing the fan, four mounting screws, an instruction manual, and two Arctic Cooling stickers.
The first thing you might notice about the F12 Pro PWM, and which is unique to Arctic Cooling, is the cage-like structure covering the fan instead of the traditional "box bezel." This is Arctic Cooling's vibration absorption design which has the fan mounted to the primary fan chassis by rubber attachments that absorb vibrations produced by the fan. Another thing you quickly notice is the "aggressive" blades that have a high-angled geometry and a complex geometry. Arctic markets the F12 Pro PWM to be a quiet fan, and I can usually tell before I ever run the fan how quiet it will be.
First, I see how the fan "free spins." Louder fans will have a "bump" as you turn the fan from the electric motor. Quieter fans will free spin for a considerable amount of time, and this is where the F12 Pro PWM falls. This often points to low vibration, high quality bearings, and although not as good as the $30 Noctua fans, its free-spin function was very good. This was anticipated since it's fitted with a fluid-dynamic bearing, which have been very smooth in every fan we've tested with an FDB.
Next, I examine the blade geometry. Having background in aerodynamics, I can tell alot about the aerodynamic noise from actually moving the air. The first thing that jumps out to me with the F12 Pro PWM is that the blade geometry is twisted so that the angle is higher the closer to the hub. This creates more even flow since the blade has a higher speed the farther from the hub, and increasing the angle nearer to the hub allows the flow at that point to "keep up" with the faster outer portions. Even flow often allows for better airflow through your case or heatsink, and also reduced noise-inducing turbulence. The other thing I notice is the tapered ends of the blades. The tapered ends help to reduce vortices on the ends of the blades, which is the largest contributor to aerodynamic noise, and is responsible for the "chop-chop-chop" found in helicopters. To see both of these "devices" in the blades allows me to predict that it will be a quiet fan, we will evaluate its actual performance in the "Final Thoughts" section next!