Intel Xeon E5 4640 's Advantages
Lower TDP (95W vs 140W)
Intel Xeon E5 1680 v3 's Advantages
Released 2 years and 4 months late
Higher specification of memory (DDR4-2133 vs DDR3)
Higher base frequency (3.2GHz vs 2.4GHz)
More modern manufacturing process (22nm vs 32nm)