Including `-d:release` optimizes it, so that's probably what he meant. It's one of the first things in the [tutorial](http://nim-lang.org/0.11.0/tut1.html http:

Including `-d:release` optimizes it, so that's probably what he meant. It's one of the first things in the [tutorial](http://nim-lang.org/0.11.0/tut1.html http://nim-lang.org/0.11.0/tut1.html).