Intel Xeon E5645 's Advantages
Lower TDP (80W vs 90W)
Intel Xeon E5 2640 v3 's Advantages
Released 4 years and 6 months late
Higher specification of memory (DDR4-1866 vs DDR3)
Newer PCIe version (3 vs 2)
Higher base frequency (2.6GHz vs 2.4GHz)
Larger L3 cache size (20MB vs 12MB)
More modern manufacturing process (22nm vs 32nm)