Hmm.....I had a problem like that on one of my fileservers....
The fileserver is a P4 2.0ghz 478 with 1gb of rambus, and ive packed 6 seagate hard drives in there, and a 600 watt psu....
Im thinking of watercooling the fossil, I had the same problem with heat.....
I bought a bunch of HD coolers, shims with fans for the rambus, and i swapped the stock fan with an ASUS StarICE PRO....and a coupld case fans....it runs way better than it did before....but it sounds like a vaccum cleaner.....
If you really wanna do something descent, watercool it.....and use liquid xp.....
Ill tell you this, with the money ive spent overhauling the fossil, i could of bought a watercooling system....and it would have been a lot quieter.....