At the last PyCon3 at Italy I've presented a new Python implementation, which you'll find at http://code.google.com/p/wpython/ WPython is a re-implementation of (some parts of) Python, which drops support for bytecode in favour of a wordcode-based model (where a is word is 16 bits wide). It also implements an hybrid stack-register virtual machine, and adds a lot of other optimizations. The slides are available in the download area, and explain the concept of wordcode, showing also how work some optimizations, comparing them with the current Python (2.6.1). Unfortunately I had not time to make extensive benchmarks with real code, so I've included some that I made with PyStone, PyBench, and a couple of simple recoursive function calls (Fibonacci and Factorial). This is the first release, and another two are scheduled; the first one to make it possibile to select (almost) any optimization to be compiled (so fine grained tests will be possibile). The latter will be a rewrite of the constant folding code (specifically for tuples, lists and dicts), removing a current "hack" to the python type system to make them "hashable" for the constants dictionary used by compile.c. Then I'll start writing some documentation that will explain what parts of code are related to a specific optimization, so that it'll be easier to create patches for other Python implementations, if needed. You'll find a bit more informations in the "README FIRST!" file present into the project's repository. I made so many changes to the source of Python 2.6.1, so feel free to ask me for any information about them. Cheers Cesare