12 fans isnt overkill unless you can take out like 3 of them and notive no difference in temps. i think you probably have a loud computer for no reason. its not really how many fans you have, but where they are positioned and how good your airflow is. 2 fans in the right place is better than 5 fans just slapped in there. a new HSF will give you the best results though. consider a nice big copper/aluminum (i thnk a mix of the 2 is best) HS and a higher RPM fan with a fan controller.