Though already few chapters into a Ruby programming book, I have very little experience with real programming and web development.

I would like to use either Ruby, or Ruby on Rails, to produce a rather simple internet application. What bothers me is suitability and performance, particularly in comparison to PHP. Speaking about a rather small app (say cooking recipes database) and shared webhosting account here.

Are the Ruby and/or RoR applications significantly more resource hungry and slower than PHP? Or are the differences insignificant.