If they do then the hardware designers failed miserably. Generally what I find is that when you first power on the machine the fans come on full. Then the bios takes over.
I can confirm that this is what happens when the s2881 is first plugged in. The fans go full speed, regardless of the BIOS.
Soif you set the fan speed really low does the system override you when you run something like cpuburn?
-- Richard A. Smith