From what I've read, this is a common problem with the QuadFX platform. The systems tend to run very hot overall. I had a similar problem with a dual FX70 QuadFX system running 64-bit Linux. With the stock factory heat sinks and fans, the CPUs would get up to ~ 58-60c at idle, then 65-70c under a load. Then the fans would kick into HIGH and cool it down, dropping back to low once the temperature dropped a bit. But that meant that I'd basically get 5-10 min. of quiet (relatively quiet anyways), followed by 3-5 min. of jet engine noise levels. The noise was irritating enough but the temperatures were very disconcerting given that the critical temperature for these CPUs is 63c. If I spent that much $$ for some high-end CPUs I sure as heck didn't want them to cook themselves just sitting there. I ended up putting in a water cooling system from Koolance. The entire kit was fairly $$ (~$900 if memory serves me right), but that was for water blocks for EVERYTHING (both CPUs, video card, both chipsets, all 3 voltage regulators, 4 HDs, and both memory banks). The only fans I have in the entire system now are 2 big slow super quiet 120mms just to keep some air flow over the motherboard. Now even under a full load the CPUs only get up to 45c and they drop to 28-32c at idle. While my set-up was rather expensive, you can get away with a much cheaper solution if you only want to cool the CPUs.
