All PWM fans will have a minimum and a maximum RPM (Revolutions Per Minute) which they can run at. In most cases, the smaller the fan, the higher the min/max RPM. For instance, a 90mm fan may have ...

Of course, the standard way of controlling CPU fans these days is with PWM, so he built a circuit which essentially converts the PWM signal from the motherboard into a phantom thermistor.

We recommend making sure your fans are up to a high standard, for both cooler and quieter PC operation. Right now, our testing points to the Noctua NF-A12x25 PWM as the best PC fan today.