Opteron 6168 's Advantages
Lower TDP (115W vs 180W)
AMD EPYC 7551 's Advantages
Released 7 years and 3 months late
Higher specification of memory (DDR4-2666 vs DDR3)
Newer PCIe version (3 vs 2)
Higher base frequency (2GHz vs 1.9GHz)
Larger L3 cache size (64MB vs 12MB)
More modern manufacturing process (14nm vs 45nm)