Intel Xeon E5 2640 v3 's Advantages
Lower TDP (90W vs 135W)
Intel Xeon E5 4655 v3 's Advantages
Released 9 months late
Higher specification of memory (DDR4-2133 vs DDR4-1866)
Higher base frequency (2.9GHz vs 2.6GHz)
Larger L3 cache size (30MB vs 20MB)