Intel Xeon E5649 's Advantages
Higher base frequency (2.533GHz vs 2.5GHz)
Lower TDP (80W vs 115W)
Intel Xeon E5 2670 v2 's Advantages
Released 2 years and 7 months late
Newer PCIe version (3 vs 2)
Larger L3 cache size (25MB vs 12MB)
More modern manufacturing process (22nm vs 32nm)