Intel Xeon E5 2669 v3 's Advantages
Lower TDP (120W vs 215W)
Xeon 6556P B 's Advantages
Released 10 years and 1 months late
Higher specification of memory (6400 vs 2133)
Newer PCIe version (5 vs 3)
Larger L3 cache size (144MB vs 30MB)
More modern manufacturing process (5nm vs 22nm)