The standard ruby interpreter is really slow (likely ~100 times slower than the Pharo 5 VM), now it binds directly multiple C librairies, such as the regex librairy, while these librairies are written in Smalltalk in Pharo. So if you measure regex performance I am pretty sure that ruby is at least 10 times faster, if not 100 times.

So basically it depends on what benchmark you are measuring. We don't do cross languages benchmarks in our servers, only versus other Smalltalks. That website (http://benchmarksgame.alioth.debian.org/) compares ruby and JRuby to VW which has similar speed to Pharo 5.