Flatt has written elsewhere that the motivation to use Chez was not speed per se but better maintainability and portability, and that required rewriting more of

Flatt has written elsewhere that the motivation to use Chez was not speed per se but better maintainability and portability, and that required rewriting more of the C core in Racket itself [0]. Doing so would have slowed down all of Racket considerably, but by using Chez it became possible without a big speed penalty. At first there was such a penalty because the rewritten stuff was still slower than C, but with tuning that has mostly gone away. [0] https://blog.racket-lang.org/2018/01/racket-on-chez-status.html https://blog.racket-lang.org/2018/01/racket-on-chez-status.h...