Intel Xeon E5 2640 v3 's Advantages
Higher base frequency (2.6GHz vs 2.1GHz)
Lower TDP (90W vs 120W)
Intel Xeon E5 4660 v3 's Advantages
Released 9 months late
Higher specification of memory (DDR4-2133 vs DDR4-1866)
Larger L3 cache size (35MB vs 20MB)