Why are you lagging in minecraft when you turn your head?

Answer 1

It means you need to change your video settings to the fastest settings.

What to do:

First you exit minecraft and reboot

Open minecraft

logg in

when it loads click options BEFORE you go into your world.

click video settings

click the graphics button untill it says fast

smooth lighting off

3d anaglyph off

guiscale auto

particles minimal

fullscreen (optional it doesn't matter which one you choose)

render distance (you want it on tiny for fastest speeds but its foggy everywhere)

performance max fps

view bobbing off

advanced opengl off

clouds off

server textures off

use vsync off

Then open your single player world and press f3

make shure your fps is above 10 or you want to turn your render distance down and get your computer over clocked IF your machine is able to handle it. it does however break you TOS (terms of service) and your warranty is then void. but it makes your computer much faster.