Intel Xeon E5620 's Advantages
Lower TDP (80W vs 135W)
Intel Xeon E5 1686 v3 's Advantages
Released 4 years and 6 months late
Higher specification of memory (2133 vs 3)
Newer PCIe version (3 vs 2)
Higher base frequency (2.6GHz vs 2.4GHz)
Larger L3 cache size (30MB vs 12MB)
More modern manufacturing process (22nm vs 32nm)