Opteron 8220 's Advantages
Higher specification of memory (667 vs 3)
Higher base frequency (2.8GHz vs 1.9GHz)
Lower TDP (95W vs 115W)
Opteron 6168 's Advantages
Released 3 years and 1 months late
Newer PCIe version (2 vs 1)
More modern manufacturing process (45nm vs 90nm)