Ty for the feedback. Hmm maybe you are right, that it takes a while for the control software to load. Still, i find it a little strange but hey could be the way Windows work. Overriding the BIOS DSDT table with registry values initially imported from the BIOS... but with an annoying delay and fan at max meanwhile. Can't come up with another explanation myself. BTW, comp came preinstalled with Vista 32-bit but i can't remember i had the same issue back then. Seems like it takes longer for Win 7 to load the "fan control software" if that is how it works. :S
Guess i have to live with it if i wanna stay with Win 7. Maybe a future driver or BIOS update will fix it. I dunno.
(Come on smart ppl, send me neat registry tweak or something...