8core Opteron 3280 SE (AM3+) with a TDP of 65 Watt observed on sale | Overclock.net
amd opteron 3365 processor has 8 cores, and is compatible with socket am3 plus, dell precision m3800,
Amazon.com: SAAKO Third Generation Opteron 1389 X4 1389 2.9 GHz Quad-Core CPU Processor OS1389WGK4DGI Socket AM3 Making Computers Process Data Faster : Electronics