Intel Xeon E5 1620 v2 's Advantages
Higher specification of memory (DDR3-1866 vs DDR3)
Higher base frequency (3.7GHz vs 2.8GHz)
Larger L3 cache size (10MB vs 8MB)
Intel Xeon E3 1515M v5 's Advantages
Released 2 years and 4 months late
More modern manufacturing process (14nm vs 22nm)
Lower TDP (45W vs 130W)