Handtweaking the CPU fan speed 2463

Rui Maciel

I've encountered three different types of fans:

1) Those that have no speed control whatsoever and are intended to run at full speed all the time. The only way you could possibly adjust those would be with a hardware hack. (Descriptions can be found on Google. Some hacks are simple knobs that you turn, others are temperature controlled. You might find one that can be software controlled.) This type of fan is quite common, IME.

2) Those that have a built-in speed controller. There's a tiny temperature sensor in the fan itself that regulates fan speed based on temperature. But there's no communication between that sensor and the computer, so there's no way for the operating system to control those fans either. (Examples would be the "SmartCool" fans from www.antec.com or the the "Thermoflow" models from www.vantecusa.com.)

3) Those that use PWM signals to control fan speed. That's usually handled by firmware on the motherboard, independent of the operating system, though. Those are the only ones you might even have a chance of controlling through application software, but that would require software to interact with the specific firmware of your motherboard that's responsible for fan control.

All of the above applies to *any* operating system, not just Linux. There's no universal method to control fan speed because it simply isn't possible with some hardware types.