Intel Xeon E5 2640 's Advantages
Lower TDP (95W vs 135W)
Intel Xeon E5 2690 v3 's Advantages
Released 2 years and 6 months late
Higher specification of memory (DDR4-2133 vs DDR3)
Higher base frequency (2.6GHz vs 2.5GHz)
Larger L3 cache size (30MB vs 15MB)
More modern manufacturing process (22nm vs 32nm)