Intel Xeon E5649 's Advantages
Higher base frequency (2.533GHz vs 1.8GHz)
Lower TDP (80W vs 110W)
Intel Xeon E5 2675 v3 's Advantages
Released 3 years and 7 months late
Higher specification of memory (DDR4-2133 vs DDR3)
Newer PCIe version (3 vs 2)
Larger L3 cache size (40MB vs 12MB)
More modern manufacturing process (22nm vs 32nm)