AMD Athlon 64 3000+ Socket 939

"If you want to build the cheapest Athlon 64 CPU out there then you can do that with the lower cost CPU and motherboard that Socket 754 offers, and if you are not concerned with upgrading that may be your best option. If you are however eyeing future upgrades, and you don't mind spending a bit more then the Athlon 64 Winchester core models on the lower end may be for you."

"...AMD has scored a home run with its line of Athlon 64 processors, which are separated into single- and dual-channel varieties. Socket-939, the premium, performance-orientated form factor, has been used as a 90nm proving ground. Model 3000+ is one such CPU that's available in both 90nm (Winchester) and 130nm (Newcastle) flavours. Comparatively low clock speed and lower heat levels, resulting from a smaller manufacturing process, made it a fantastic candidate for overclocking."