To be fair, The README.md seems to be three years old.

It would actually be quite interesting to see a comparison with all of the languages using more recent builds to see which ones are developing their performance.

Yeah, I've meant to update it and add more language implementations, but haven't really got the time. Might as well do so soon as almost all compilers/interpreters have new versions which I suspect have many nice optimizations.

Nim 0.14 is also from more than 3 years ago.