Further quietening the Soltek Qbic eq3702

Hi all,
just got myself a Soltek qbic eq3702. Even on "silent" its louder than my old (dead) system. Does anyone know where the main source of noise is generated? if its the large exhaust fan can I pop a zalman fanmate from my old cooler on the cable and turn it down?
I'm currently running:
Barton 2500+ @ FSB200 3200+
2x crucial 512mb 3200 ddr
plextor 708a
samsung spint point p80 160gb
currently using onboard as my Radeon 9600XT ultimate is being RMA'd

I'd be happy to run at 333 fsb and maybe even underclock so I can get it silent-ish.