Update v1.6.11:

This effects save files with lots of items in the world.

Additionally please remember to use the 'Toggle Save Dirt Chunks' and 'Toggle Save Raw Resources' options in the gameplay settings menu if you have lots of dirt/resources in your base, this will help with FPS.

This is not the 2.0 optimisations, they will be much much much better.

This will break the Logic Extended and Pipe Extended mods, please remove these before playing. I'm going to be working with the mod developers to get these fixed asap.