AMD Athlon X2 6000+

The AMD Athlon 64 X2 6000+ has 1MB of L2 cache per core and is still manufactured on the 90nm process, so in terms of energy efficiency and overclocking it should have the same characteristics that AMD users have become accustomed to. By remaining on the 90nm process it makes for an easy upgrade to exisiting motherboards as a BIOS upgrade is not required and th 90nm processors have lower memory latency over the new 65nm parts.