Intel Xeon E5 2665 's Advantages
Higher base frequency (2.4GHz vs 1.9GHz)
Intel Xeon E5 4640 v3 's Advantages
Released 3 years and 3 months late
Higher specification of memory (1866 vs 3)
Larger L3 cache size (30MB vs 20MB)
More modern manufacturing process (22nm vs 32nm)
Lower TDP (105W vs 115W)