CakePHP vs codeigniter - I'm experienced in CakePHP [closed]
This thread will give you a fairly good answer, as the site in question is not a "Hello World" but a fully fledged Site with database access helpers and libraries loaded, etc...
I'm sure some will have arguments about its validity (probably CakePHP proponents), but it's not every day you have a site re-developed between frameworks and compared.
UPDATE
Again, for those that don't want to follow the link to the thread, the tester actually upgraded the site to CI 2.0, using modular extentions, caching, other optimizations and re-tested