More than you cared to know about PC fans
Also, one thing I&#x27;ve always wondered: why do people <i>want</i> to use hwmon to set fan RPMs? (Or really, why do this from userspace at all?) It seems inherently dangerous to me, as you&#x27;re asking a process who might not receive CPU time for whatever reasons from the very much not realtime OS to control a fan; if the current RPM is too low, and the system starts generating heat, but the fan controlling process doesn&#x27;t get CPU time … then what happens?<p>It seems to me you want fans controlled with something dedicated to it.<p>The other thing I don&#x27;t get is all the plethora of options my motherboard gives me to set fans only to fixed RPMs. Am I crazy in that I want the fan to be controlled by heat? (More heat =&gt; more RPMs. Keep the system cool, but if there isn&#x27;t much thermal load, spin the fans down and reduce the noise?)<p>But by fixing an RPM, it seems the only valid input is &quot;100%&quot;; anything else could be too low under stressful conditions.<p>I could also have a cheap motherboard. (I definitely won&#x27;t be purchasing from this manufacturer again, and the motherboard does have other severe quality issues…)