Intel Xeon E5 2666 v3 's Advantages
Higher base frequency (2.9GHz vs 2.3GHz)
Lower TDP (135W vs 145W)
Xeon 6516P B 's Advantages
Released 10 years and 3 months late
Higher specification of memory (4800 vs 2133)
Newer PCIe version (5 vs 3)
Larger L3 cache size (80MB vs 25MB)
More modern manufacturing process (5nm vs 22nm)