Yea, you're right. The problem is that the BIOS is kinda strange...I can only set the time, date and which device I want to boot from =) Nothing else...I guess it must be some way to access stuff like ports, memory, fan control, thermal zones and so on from BIOS.
And now when you said this, it came on my mind that even while Windows's booting up the fan goes on and works for a while just to cool down the CPU a bit. So it might be hardware-detected.
Thanks eadz, your help is appriciated.