the single-thread case ran a little slower than it should on this live demo due to a mistake on my part: `run` redirected to the Rust interpreter, rather than the C interpreter. the Rust one is a little bit slower. the numbers on the site and on all docs are correct though, and the actual speedup is ~12x, not ~16x.

I apologize, I gave you the wrong answer.

I thought you was talking about the DEMO example, which ran ~30% slower than expected. Instead, you were talking about the README, which was actually incorrect. I noticed the error and edited it. I explained the issue in another comment.

Its possible to see such scaling if involving any level of cache or I/O.