Thanks (to all correctors). FWIW, that zlib-ng discussion page you link to has way more information about what machine the benchmarks were run on than TFA. It's also a safe bet that Google timed their chromium lib (which seems really close) on a much larger diversity of core architectures than these 3..4 guys have with zlib-rs. So, you know, very early days in terms of perf claims, IMO.

Also, FWIW, that zippy Nim library has essentially zero CPU-specific optimizations that I could find. Maybe one tiny one in some checksumming bit. Optimization is specialization. So, I'd guess it's probably a little slower than zlib-ng now that this is pointed out, but as @hinkley observed, portability can also be a meaningful goal/axis.