I'd be amazed if TruffleRuby could beat Crystal, given the problems most JITs have had with Ruby. By restricting the extreme dynamism of Ruby a bit, Crystal can allow for optimalisations that no Ruby implementation will be able to match. It's just really difficult to properly compile languages where it's possible to dynamically redefine the + operator based on input from HTTP requests. That said, Truffle is looking super cool and Crystal does not have anything near the size and quality of the Ruby ecosystem yet.