Xeon absolutely crushes EPYC on MySQL Sysbench. The top-of-the-line EPYC provides performance similar to the five-year-old Xeon E5 v3 (Haswell) from Intel, except at high thread counts where that obsolete Intel part also crushes the EPYC. These results are on Percona's own blog and are also backed up by Anandtech's reviews where Skylake Xeons are ~twice as fast as AMD's.

For large codes there is just no getting around the fact that the AMD parts have a weird and highly fragmented cache architecture, very slow memory access, NUMA memory latency even on the same socket, and a frankly broken branch target buffer. Xeon has none of these problems.