hp/asus notebooks : going very hot, dont know why.

[hd77]

hello

unfortunately since a week I was wondering about something :
on two old hp elitebook, it looks like under win7 and linux/LMDE, that at a general glance everything looks correct
but on openbsd, something happens, even if CPU is not high : it's a huge overheating, with fans going almost everytime in the high speed, and lower case of the laptop, almost burning (in a way it's really warm, impossible to get it a minute on laps)

I saw the same problem on an asus laptop.

is there anyway to know where it come from?
under win7 and linux, this problem doesnt happens. It's really strange.

thak you for ideas