Intel Xeon E3 1220 's Advantages
Lower TDP (80W vs 130W)
Intel Xeon E5 1620 v2 's Advantages
Released 2 years and 5 months late
Higher specification of memory (1866 vs 3)
Higher base frequency (3.7GHz vs 3.1GHz)
Larger L3 cache size (10MB vs 8MB)
More modern manufacturing process (22nm vs 32nm)