Intel Xeon E5649 's Advantages
Larger L3 cache size (12MB vs 10MB)
Lower TDP (80W vs 130W)
Intel Xeon E5 1620 v2 's Advantages
Released 2 years and 7 months late
Higher specification of memory (1866 vs 3)
Newer PCIe version (3 vs 2)
Higher base frequency (3.7GHz vs 2.533GHz)
More modern manufacturing process (22nm vs 32nm)