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 (1866 vs 3)
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)