You should have put this in the relevant section for the forum belonging to the phone you have...
At the very least, I suggest changing the CPU govenor and IO schedulers. You can Google about them and find out which is more suitable to your needs. But ZZMove (if you're on the i9300) and row are good options (again, googling will reveal more about these).
But, remake your thread in the proper section for your phone. More people will answer then. I found this by accident via Google.