Interesting, I'm able to repro this locally: https://gist.github.com/oconnor663/57ece045df23fe977228aae0cd3ae189 https://gist.github.com/oconnor663/57ece045df23

Interesting, I'm able to repro this locally: https://gist.github.com/oconnor663/57ece045df23fe977228aae0cd3ae189 https://gist.github.com/oconnor663/57ece045df23fe977228aae0c... input bytes: b'hello world' average SHA-256 iteration time: 284 ns average SHA-512 iteration time: 470 ns average BLAKE2s iteration time: 231 ns average BLAKE3 iteration time: 355 ns For comparison, in short-input Rust benchmarks on the same machine, one block of BLAKE2s (SSE41) is 77 ns and one block of BLAKE3 (AVX512VL) is 43 ns. So whatever's happening here, I think it's dominated by Python overhead.