The probes are precise, fan speeds range from 40 to 100% (below 40% it is impossible, we go directly to 0%, the fan stops). The automatic mode is useful if you never want to worry about having a PC that heats, the speeds are adjusted in temperature. And if you want a cathedral of silence, we can even stop any (for a global temperature increases of course, but in the short term as when watching a movie, it can be highly useful and increases the temperature of the tower a few degrees in my case), and more enjoyable if you turn off the LCD screen by pressing 3 seconds on the bottom right button). The Rhéobus is very complete with lots of features useful enough as the alarm that locks after a predefined threshold temperature, the deactivation of beeps which can become quite annoying, the ability to turn off the screen as I said , display in ° C and ° F ... I highly recommend! Finally, rather coldly haha;)