Single Player Block Lag - Minecraft?

Hi, In one of my custom map worlds I'm getting a huge amount of block lag. My client does not lag as I get about 150 fps. I'm running 14w27b and the redstone is in the spawnchunks, Here is a gif showing the lag. Sorry the gif is choppy. My avi to gif converter isn't very good

http://www.gfycat.com/PoliteEssentialFlickertailsquirrel

Guest

Optifine? Search that and download that.
It reduces lag a lot.

If it proves ineffective though, it could be that your computer simply can't handle the graphics.

SnowStorm