for what it's worth...i have the same ZALMAN heatsink fan...running a p4 3GHz on an ASUS P5RD1-V...
and i don't know a whole lot LOL i'm new to all this myself, but just from my own experimentation, i found that using the ASUS Q Fan feature actually yields higher temps. i just turned it off, and my temps are solid at 46-47 deg. but with Q Fan enabled, temps go to 60+ deg. i have the fanmate turned all the way clockwise.
don't know if that means a whole lot