Lagging Camera and Keyboard App.

I'm using a rooted Zenfone 2 551ML and i'm on stock Asus ROM, my problem is that when i take a picture using the stock camera app, it takes like 2 seconds to load before i can take a picture again. Also, while i'm chatting with someone over the Messenger app by Facebook, the keyboard pop ups lag sooo much that sometimes it renders the keyboard unusable since it's covering the letters. All software are up to date.

Does anyone else have this kind of problem, and if you have experience the same problem is there a fix for this?