Intel Xeon E5 1620 's Advantages
Higher base frequency (3.6GHz vs 3.5GHz)
Larger L3 cache size (10MB vs 8MB)
Intel Xeon E3 1275 v3 's Advantages
Released 1 years and 3 months late
Higher specification of memory (DDR3 vs DDR3)
More modern manufacturing process (22nm vs 32nm)
Lower TDP (84W vs 130W)