Xeon E7 4820 's Advantages
Larger L3 cache size (18MB vs 10MB)
Lower TDP (105W vs 130W)
Intel Xeon E5 1620 v2 's Advantages
Released 2 years and 5 months late
Higher specification of memory (1866 vs 1333)
Higher base frequency (3.7GHz vs 2GHz)
More modern manufacturing process (22nm vs 32nm)