2.3-2.5 what improved?

[Robin Becker]

A large cgi based web Python-2.3 application needs to be speed improved. 
experiments show the following under reasonable testing (these are 2 second 
reportlab pdf productions)

1) 2.3 --> 2.5 improvement small 1-2%
2) cgi --> fcgi improvement medium 10-12%

I sort of remember claims being made about 2.5 being 10% faster than 2.4/2.3 etc 
etc. Can anyone say where the speedups were? Presumably we have a lot of old 
cruft that could be improved in some way eg moving loops into comprehensions, 
using iterator methods etc. Are those sort of things what we should look at?
-- 
Robin Becker