JSON encoding test at TechEmpower, CodeIgniter vs PHP.

> The reason for the slow performance for single-queries (as I read their code used for the tests) was the use of CodeIgniter-2 (but a bigger reason was) and using mysql driver in CodeIgniter and for PHP they used PDO driver (I reported that issue).

Did you confirm that? If you change it to PDO_MySQL, the performance increases?

> Can anyone tell me why does this function run slower comparing to the raw-php code?

Every framework is slow. It does a lot of things before running code in controllers.

They are using raw queries inside CodeIgniter, so if the overhead of query builder class isn't added, queries should perform the same or with a minor difference. If still there is huge difference, the reason possibly could be the database driver used, which is mysql driver in that case.