Ruby 2.1.0 (released on the very end of previous year) introduced many performance improvements, about which you can read here https://www.ruby-lang.org/en/news/2013/12/25/ruby-2-1-0-is-released/. In fact, Ruby core developer Aman Gupta published earlier today nice post about how GC works now.

How much faster can Ruby 2.1 be in day-to-day workflow? I've decided to give it a try and checked on one of our apps with ~600 tests and 1600 assertions.

Intel(R) Core(tm) i5-2500 CPU @ 3.30GHz x 4 / 8GB RAM / SSD (Ubuntu 12.04)