5x-10x differences only exist between statically compiled and dynamically compiled languages. The differences in performance between dynamic languages is marginal. As for Ruby it's now slightly faster than Python for most things except C-based numerics.
When you start mixing in things like random number generators, different methods of string manipulation, different data structures and so on, there can be pretty dramatic differences in performance within each category. (static or dynamic)
Every language has building blocks that come with it that are far from equal.
