Grid computing is fast emerging as the solution to the problems posed by the massive computational and data handling requirements of many current international scientific projects. Simulation of the Grid environment is important to evaluate the impact of potential data handling strategies before being deployed on the Grid. In this paper, we look at the effects of various job scheduling and data replication strategies and compare them in a variety of Grid scenarios, evaluating several performance metrics. We use the Grid simulator OptorSim, and base our simulations on a world-wide Grid testbed for data intensive high energy physics experiments. Our results show that the choice of scheduling and data replication strategies can have a large effect on both job throughput and the overall consumption of Grid resources.