You mean at any speed? Or just when you play on speed 2 or 3?
Lag and stutters can be caused by lots of different things. 
It might be that something is interferring with the game (for example, a firewall, or another application or process in the background).
It might be too many hearthlings too busy or in the night.
It might be a graphics booster or CPU overclocking or the like.
It might be a performance issue with some subsystem of the game (the team keeps working on performance).