AMD EPYC 7542 's Advantages
Higher base frequency (2.9GHz vs 2.1GHz)
Lower TDP (225W vs 390W)
AMD EPYC 9845 's Advantages
Released 5 years and 2 months late
Higher specification of memory (6000 vs 3200)
Newer PCIe version (5 vs 4)
Larger L3 cache size (320MB vs 128MB)
More modern manufacturing process (3nm vs 7nm)