Intel Xeon E5 1620 's Advantages
Higher base frequency (3.6GHz vs 1.6GHz)
Intel Xeon E5 2603 v3 's Advantages
Released 2 years and 6 months late
Higher specification of memory (1600 vs 3)
Larger L3 cache size (15MB vs 10MB)
More modern manufacturing process (22nm vs 32nm)
Lower TDP (85W vs 130W)