Having just built a new AMD powered (1900+) system, I've found those chips to run very hot. The CPU heatsink I started with was a Volcano 7, and I can't recommend this unit. The Volcano 7 has a variable speed fan controlled by a temperature probe. Sounds good in theory, the fan runs slower when the CPU is cool, thus producing less fan noise. In practice however, my CPU temps would quickly rise to my cutoff temp of 60 degrees C under load.
Why? Well the temperature probe for the fan is mounted outside the heat sink, and thus is not measuring CPU temp but case temp. My case is a Lian Li PC-60 USB, which provides very good cooling overall. Because the case temps were so low (under 30 degrees C), the CPU fan never ran fast enough to cool the CPU under load.
I tried moving the temperature probe inside the heatsink but that wasn't very successful. I solved the problem but cutting off the probe and hardwiring the fan to the full on position. That worked great, but was very noisy.
The ultimate solution was a new heatsink, the AX-7, with a Mechatronics 80x80x25mm Fan (Ultra High Speed) mounted on top. Got mine from
http://www.coolerguys.com, along with a tube of Artic Silver 3 heat sink compound. Everything is nice and quiet now, I was even able to turn my case fans down a notch. Idle temps are 38 C and under load 45 C. The CPU is not overclocked, but my GF3 Ti200 is clocked up to ti500 levels.
Haven't flown the new rig in AH yet as it is USB only (Abit AT-7 MAX motherboard) and my Cougar hasn't arrived yet. It screams in Dungeon Siege though...
-Smut