Intel Xeon E3 1270 's Advantages
Higher base frequency (3.4GHz vs 2.6GHz)
Lower TDP (80W vs 135W)
Intel Xeon E5 1686 v3 's Advantages
Released 3 years and 5 months late
Higher specification of memory (DDR4-2133 vs DDR3)
Larger L3 cache size (30MB vs 8MB)
More modern manufacturing process (22nm vs 32nm)