Xeon E 2456 's Advantages
Released 6 years and 6 months late
Higher specification of memory (DDR5-4800 vs DDR4-2400)
Newer PCIe version (5 vs 3)
Higher base frequency (3.3GHz vs 2.1GHz)
Lower TDP (80W vs 120W)
AMD EPYC 7251 's Advantages
Larger L3 cache size (32MB vs 18MB)