Low frame rate for mob spawns and arrows

In the realm/server that I have payed for, when I spawn mobs or when I shoot arrows, they have very low frame rates, and move in a blocky fashion. To go further into detail of what I mean, it looks as if these mobs have a bad internet connection, and almost rubber band across the map but at a slow pace. I hope I have made my problem clear. Thank you for your time.