you can download speed fan and you can lower the rpm or raise it
i can control my cpu fan and my chipset fan throught speedfan. i turned all my fans off lol and waited aroudn 10 seconds and my temps started to go up to 35C lol. and i turned them back all on high.
EDIT: make sure you know which one is the chpset fan and which one is the cpu fan, i believe fan2 is my chipset fan
AIM/Xfire - pzerofgh