What value are you using for TickLength? How does this value compare to the small times steps you are using to model the flow of material?
Changing the TickLength input should not have any affect on execution speed or on the model results. The fact that your model is faster with a larger value for TickLength indicates that this value is too large and that you have introduced a systematic error. You should leave the TickLength input at its default value.
If you are trying to model the flow of material, you should consider using JaamSim Pro (jaamsimpro.com
) which is designed for this type of model and is extremely fast. The cost to license the Pro version is comparable to Arena, Simio, etc. so this would have to be a paid modelling assignment. We are not providing a student version at this time.