AMD EPYC 7643 's Advantages
Released 3 years and 9 months late
Higher specification of memory (DDR4-3200 vs DDR4-2666)
Newer PCIe version (4 vs 3)
Larger L3 cache size (256MB vs 64MB)
More modern manufacturing process (7nm vs 14nm)
AMD EPYC 7451 's Advantages
Lower TDP (180W vs 225W)