That would mean something if Ruby apps are 100% Ruby and/or are performing binary tree operations all the time, or doing similar kinds of CPU-intensive operations as depicted in the alioth benchmarks. But they don't. Ruby web apps perform lots of string manipulation, memory allocation, I/O. A lot of expensive things are offloaded to C libraries. Things like XML parsing are offloaded to native libraries like libxml; nobody uses an XML parser fully implemented in Ruby. Ruby does not reimplemented gzip compression in Ruby, it uses zlib. So the alioth benchmarks are not representative of real-world performance.
Order of magnitude faster? I doubt that. Unless the old ones were really old / slow to begin with. But really, we are both speculating without knowing the facts.
I am curious how much a rewrite staying in Ruby could have saved. Its always easier to write code when you have a good specification, and a working application would fulfill that role well.
