AMD Opteron Model 142 1.6GHz 64-Bit PROCESSOR CPU - Retail : 320 $
AMD Opteron Model 144 1.8GHz 64-Bit PROCESSOR CPU - Retail : 460 $
AMD Opteron Model 842 1.6GHz 64-Bit PROCESSOR CPU - OEM : 1295 $
AMD Opteron Model 844 1.8GHz 64-Bit PROCESSOR CPU - OEM : 2200 $
(http://www.newegg.com)