Intel Xeon E3 1585 v5 's Advantages
Higher base frequency (3.5GHz vs 3.3GHz)
Lower TDP (65W vs 80W)
Xeon E 2456 's Advantages
Released 7 years and 7 months late
Higher specification of memory (DDR5-4800 vs DDR3)
Newer PCIe version (5 vs 3)
Larger L3 cache size (18MB vs 8MB)
More modern manufacturing process (10nm vs 14nm)