The only time Ruby or Python are fast is when the program is not running Ruby or Python but running some C code underneath. If your programs only consist of that, you can very well say "this ‘Ruby/Python’ code is fast". But as soon as you have something that isn't in your standard library, welcome to the actual language, and welcome to performance problems.
You should really check out Alex Gaynor's slide deck. Nothing I said disagrees with what you've said here, provided you take the entire thing in context.
http://benchmarksgame.alioth.debian.org/u32/benchmark.php?te...
http://benchmarksgame.alioth.debian.org/u32/benchmark.php?te...
and so is Python:
http://benchmarksgame.alioth.debian.org/u32/benchmark.php?te...
The only time Ruby or Python are fast is when the program is not running Ruby or Python but running some C code underneath. If your programs only consist of that, you can very well say "this ‘Ruby/Python’ code is fast". But as soon as you have something that isn't in your standard library, welcome to the actual language, and welcome to performance problems.
Elaborating on the implications of this: whenever you actually _use_ the language to do some abstraction, you pay heavily for it: http://bos.github.com/reaktor-dev-day-2012/reaktor-talk-slid...