Intel Xeon E5 1620 's Advantages
Higher base frequency (3.6GHz vs 3.3GHz)
Larger L3 cache size (10MB vs 8MB)
Intel Xeon E3 1226 v3 's Advantages
Released 2 years and 2 months late
Higher specification of memory (1600 vs 3)
More modern manufacturing process (22nm vs 32nm)
Lower TDP (84W vs 130W)