Horses are lagging my minecraft like CRAZY.

I spawned over 1000 horses.
This is an old post.

I've been on a really good singleplayer survival world and 1.5.2 duplication glitch in minecraft.

I have some screenshots of my survival world

I also found a 1.5.2 sp multi duplication glitch.  You go in as 2 players, put some stuff in inventory, one at a time, open to lan, both go in, send all items to host, and wala!