Intel Xeon E5 1620 v2 's Advantages
Higher specification of memory (1866 vs 4)
Higher base frequency (3.7GHz vs 1.5GHz)
Larger L3 cache size (10MB vs 1.5MB)
Intel Xeon D 1557 's Advantages
Released 2 years and 5 months late
More modern manufacturing process (14nm vs 22nm)
Lower TDP (45W vs 130W)