CakePHP or CodeIgniter for file sharing webapp?

I am building a web app designed to provide users with file-sharing ability, this is a safe app as the service is paid and will be using Stripe Payment API

However I can't decide which php framework would be the best for this task. I am very clear that this can be done with both, but I want the framework to be light on the server and not eat allot of server resources like RAM and CPU as I am limited at this moment, but should the app grow higher then resources will be increased.

I looked at Code Igniter and CakePHP. In my view CakePHP seems much more lighter then CodeIngiter but I never used either one so I can't judge. All I need the framework to do is

Provide up-most security possible against XSS, Injections

Able to work with file system and amazon s3

Play nice with amazon s3 and provide easy upload method to s3

Provide simple template scheme

Provide fastest possible database and general response time

Work with Stripe Payment API

Work with PHP 5.3.x and MySQL 5.3.x as efficiently

This is really it, if you can provide some pro feedback on which one would do the best or just do great for the task of file-sharing and dealing with files in s3 please let me know. Thanks in advance.