Huge Lag/Glitch Issue

I have been playing alot of survival lately and there has been some issues I've noticed. My first issue is that since I've downloaded 1.4.7 there has been an extreme amount of lag! I've looked up on many different sources on how to fix this. Such as: Google and youtube and nothing has worked! I even redownloaded minecraft from the minecraft website and nothing changed. I would just like to play the game could you please fix this!