I bought a Thermaltake lathe with a single fan (Thermaltake) noisy. I replaced the latter by 3 Noctua fans: - NF-S12B ULN (Ultra Low Noise) to 700 rev / min which draws air down the front to cool hard drives; - NF-S12B FLX one that I set at 600 rev / min which rejects the air on the top rear of the tower; - NF-P14 FLX one I adjusted to 750 rev / min which rejects air from the top of the tower. 3 ventilos Noctua are very quiet, we hear only the CPU fan that I also may one day restore to a Noctua. The fan speed is set with a cable on which there is a resistance, which reduces the current to the fan and therefore its speed. At rated speed (1200 rev / min), the FLX are a bit noisy, but they are quiet and effective at low speeds. The ULN model is very quiet, but its maximum speed is 700 rev / min, and air flow is low, so I'm using that for hard disks but not for motherboard and its components.
