"The Intel processor has nifty 256-bit SIMD instructions. The Apple chip has nothing of the sort as part of its main CPU. So I could easily come up with examples that make the M1 look bad."

The M1 has 128-bit NEON SIMD, and given its decode pipeline and cache efficiency it seems more likely to actually benefit entirely from it. AVX on Intel devices is often of limited value because it's either memory starved or gets throttled (many SKUs throttle once you start using AVX).

I've had cases where vectorizing ongoing sequential processing in the most optimal fashion available barely gave a single digital percentage increase. 9 times out of 10 it's snake oil.

But regardless, if there's an example that would make the M1 look bad, do it.