Take a look at the following forum thread over on crestfall-gaming.com:
 
	http://forums.crestfall-gaming.com/index.php?/topic/788-vanilla-wow-112-stuttering/
 
	I'm not a rocket surgeon when it comes to understanding the game client code, but it appears that it's a client side issue with timers not syncing with your current systems refresh rate.  To work around it, use your GPU properties to force a refresh rate of 64Hz (instead of 60Hz, for example).  That should clean up nearly all of the visible stuttering.
 
	-Thrick