Intel Xeon E5 1620 v2 's Advantages
Higher base frequency (3.7GHz vs 3.5GHz)
Lower TDP (130W vs 135W)
Intel Xeon E5 2637 v3 's Advantages
Released 1 years late
Higher specification of memory (DDR4-2133 vs DDR3-1866)
Larger L3 cache size (15MB vs 10MB)