It's hard, if not impossible to do meaningful comparison of php and
python _framework_ speed since the simpler the app (and hello world is
as simple as it gets), the more the web server/interface tech will
influence the result. So, even with web2py on it's own, you will see
drastic differences depending on whether it's running as a CGI,
cherrypy, mod_wsgi, mod_python, can it be precompiled, etc. On the
other side, PHP uses technologies which you also would have to explore
to make a meaningful picture, like mod_php versus fastcgi, mmcache
style caching accelerators, etc. If you compared it to Django,
TurboGears et al, it would be a much more lifelike comparison since
they are 'the competition'. PHP frameworks might serve the same
purpose, but are technologically pretty far (thus if you compare PHP,
you might as well compare ASP, JSP and their kin).