Some modeling projects can become quite large, in which case there are a few ways you can enhance the modeling performance:
•Make sure that you are using the latest driver for your specific graphics card (resolve this before addressing the following tips)
•Disable syntax coloring (from the Styles window, set the property Use Syntax Coloring to false).
•Disable "gradient" as a background color for diagrams, use a solid color (from the Styles window, set the property Diagram background color to a solid color, for example, white).
•Deactivate automatic completion (go to Tools | Options | Diagram Editing and clear the check box Enable automatic entry helper).