Intel Xeon E3 1275 v2 's Advantages
Higher base frequency (3.5GHz vs 2.1GHz)
Lower TDP (77W vs 120W)
Intel Xeon E5 4660 v3 's Advantages
Released 3 years and 1 months late
Higher specification of memory (DDR4-2133 vs DDR3)
Larger L3 cache size (35MB vs 8MB)