It is going to depend on what is in the document. If it were simply text, I doubt this would happen. It may be related to your display adapter, especially if you got suckered into installing Win 10.
Consider using
Collapsible Headings and the Navigation Pane for moving around/scrolling.
Why use Microsoft Word’s built-in heading styles? by Shauna Kelly
Use Styles for most of your formatting. This makes for a much less complex document structure.
Understanding Styles in Microsoft Word