Sorry for being dumb, I thought I've enabled it in ./cargo/config.toml for rust. Checked it again and it appears that I did not (the file name was wrong). -marc

Sorry for being dumb, I thought I've enabled it in ./cargo/config.toml for rust. Checked it again and it appears that I did not (the file name was wrong). -march=native for CLang also did better than just avx2 rust - By-Copy: 1831, By-Borrow: 1850 c++ - By-Copy: 2411, By-Ref: 2458 Interesting why Rust wins with such a large margin. Maybe will try to find out later.