My fw-21m fans working all the time after upgrade

Hi,
I have a VAIO FW-21M and after the upgrade of my kubuntu from 8.10 to 9.04 (64-bit version) and later the clean installation of ubuntu 9.04 fans don't stop working. When I was using 8.10 my laptop was completely quiet. Can anybody help to make my laptop quieter? Thanks in advance
Update:
I install cpu frequency scaling monitor and cpu frequency monitor and I can say that there is an improvement, but still the fans are not as quiet as they used to in 8.10