To get the maximum performance from the Giant Squid I recommend only the following premium quality 120mm fans. All are well-engineered, have high static pressure, are reliable, and most importantly, are very quiet. There are a few factors that affect fan choice: ASIC Frequency: 500 - 800Mhz - the NF-F12 5V PWM (0-1500rpm) is silent at default Bitaxe settings and very quiet even at full speed. Plugs directly into the Bitaxe for automatic speed control. The quietest fan I recommend that still has great airflow and static pressure. 500 - 900Mhz - the NF-A12x25 5V PWM (0-1900rpm) is extremely quiet at stock settings and a low woosh at full speed. Plugs directly into the Bitaxe for automatic speed control. Higher static pressure for restrictive heat-exchanger styles like the 52pi Low-Profile Plus. Above 900MHz - the increased heat production at these settings requires a very large airflow that 5V fans cannot provide. There are several high quality 12V fans that I recommend, based on your cooling needs and how much noise you are willing to accept! NF-A12x25 FLX (1350, 1700, 2000 rpm selectable with cable adapter) beQuiet! Silent Wings Pro 4 (1600, 2500, 3000 rpm selectable via switch). High flow and high static pressure for maximum cooling. Much quieter than competitive fans relative to the amount of airflow and cooling realized. Really nice German-engineered fan with switch to select maximum rpm. Three types of corner mounts included for frame sealing, different looks, different mounting posts, and vibration isolation. NF-F12 iPPC-3000 (3000 rpm) - tons of air. You'll hear it! Ambient Temperature - if you live in a warmer climate with no air conditioning, your Bitaxe will need more airflow (rpm), especially if you over-clock. Noise - if your Bitaxe will be on your desk, or in the same room with family or co-workers you will want a quieter fan. Heatsink Size - a shorter heatsink will need more airflow (rpm) than a taller one at a given over-clock frequency. Heatsink Surface Area - the more surface area the better it will cool Heatsink Mass - the more mass the more heat it will absorb and retain Heatsink Type - Conventional heatsinks are less restrictive and more forgiving of a fan with lower static pressure. Heat-exchanger styles such as the 52pi Low-Profile Plus are more restrictive and require higher static pressure fans to fully utilized their cooling capability.
