As a sibling quote mentioned, 1.9 is fast relative to 1.8. JRuby is pretty fat in general, with the potential to approach Java speed at times, although I think specific things can slow you down a lot. In particular it was the case (not sure if it still is) that exceptions in JRuby were pretty expensive, but many Ruby libraries treat them as cheap, leading to performance problems if you move from one platform to another.

I was not trying to be precise though, just give a feel for the different implementations.

Than 1.8, as per the part you trimmed from your quote..