Intel Xeon E5 2643 's Advantages
Higher base frequency (3.3GHz vs 1.9GHz)
Intel Xeon E7 4820 v3 's Advantages
Released 3 years and 3 months late
Higher specification of memory (1866 vs 3)
Larger L3 cache size (25MB vs 10MB)
More modern manufacturing process (22nm vs 32nm)
Lower TDP (115W vs 130W)