laravel4 response very slow and take much time to load
This is not an issue with Laravel, it is most likely an issue with how your server is configured. Most likely it could boil down to how you have Apache/Nginx configured, where and how you are loading your static assets and other variables.
By the sounds of it, you are using a stock version of Laravel and stock version of PHP, the only difference between the two being which PHP features one another supports and the structure of the applications themselves. In my personal benchmarks Laravel is undeniably faster than Codeigniter due to lazy loading. Have you tried running the same tests on a different server or even locally on your own machine?