The stock AMD cooler with 2-4 heat pipes is pretty good (obviously the 4 heat pipe version is superior to the 2 heat pipe version)... do you already have one of those coolers? If so I'd see what you can do on that cooler before spending money on an upgrade that might only get you another 100-200MHz. My Opteron 165 did 2.7GHz on the 4 heat pipe version without a sweat. I pushed it further, but settled on 2.7GHz as I was happy with the voltage and temps.