Horse lag/fps drop

Started a new world and got a tame horse and put a saddle and diamond armour on it and when I go to ride it it lags/frame rate drops rendering riding a horse pointless because running on foot is faster.

I thought it might be the running water problem so took the horse all over my map and it does the twitching fps thing no matter what direction I point or where go.

This is a new world with no red stone or item signs.

Survival mode with City TP, Single-Player, on-line mode