Here's someone who wrote a load library routines in asm and claimed they were faster.

https://old.reddit.com/r/programming/comments/dygsvm/heavyth...

I was skeptical, so I looked into his zlib implementation. It was 18% faster than gzip v1.6. The author said, "all I did was hand-compile the reference implementation, an 18% reduction in user-space time is a big advantage IMO."

I am not skeptical any more! More details of the benchmarking are in the linked thread.