MKL's benchmark performance requires AVX + FMA.
3.5 GHz * (4 add + 4 multiply) * 2 fma/cycle = 56 peak GFLOPS.
To exceed 50 GFLOPS without them would imply the CPU ran at 12.5 GHz.
OpenBLAS, on the other hand, actually performed poorly because it was limited to SSE thanks to a bug preventing the CPU from being recognized as Zen2.
Small matrix multiply benchmarks on a Zen2 (Ryzen 7 4700U), featuring MKL 2020.1.216+0, OpenBLAS, and Eigen: https://gist.github.com/stillyslalom/bd916e3d26b4531364676ac...
MKL's benchmark performance requires AVX + FMA. 3.5 GHz * (4 add + 4 multiply) * 2 fma/cycle = 56 peak GFLOPS. To exceed 50 GFLOPS without them would imply the CPU ran at 12.5 GHz.
OpenBLAS, on the other hand, actually performed poorly because it was limited to SSE thanks to a bug preventing the CPU from being recognized as Zen2.