Review on Noctua NF F12 IPPC 3000 PWM Computer Components by Wiktor Redziski ᠌

I put two such fans at the output in series, one after the other, tightening them with M4 screws. The head had to be ground down to a diameter of 5.6 mm, and a groove was made in the nut on one side so that it would also not be removed into the stiffener. The screw was cut to the minimum length, so that it was enough for the thickness of the fan ears and the nut - otherwise the screw would not fit between the ears. I left shock-absorbing rubber pads on each fan only on one side, on the exit side. When tightening with screws, the rubber gaskets shrunk and there was no gap between the fans. I did all this in the calculation to reduce noise at the same performance. I don't know how much this affected the noise, but the rpm range has expanded, on my motherboard: the minimum is 532, the maximum is 3370, see Fan2. I don’t know how much the volume of air pumped increased, obviously not twice if I installed them in parallel. Here only it can be expected that the pumping pressure will be 2 times higher. I have two fans in parallel at the input of the system unit: Titan TFD-12025H12ZP and Deepcool GS120; and so, at full speed of all fans, the thread brought to the ventilation holes on the rear wall of the case is attracted, and not protruded. Therefore, the air blown in by these two fans is not enough to drive our hero through the tandem, and he still him in from the side. As for the noise, up to 800 rpm the noise of these fans does not stand out from the background of the rest, but a rumble begins to appear higher up, and at maximum speed it turns into almost ringing. These blades cut the air against the equalizer plates (separator, if by ogy with a gas turbine engine). But without these plates, it would not make sense to put fans one after another, the first one would spin the air, and the second one would idle like a weather vane.