Speed Up Word's Performance When Scrolling
The Problem:
When I start to scroll, Word X goes all glacial on me. Any ideas?
The Solution:
This sounds like the notorious problem of Live Word Count consuming every spare processor cycle. Try turning off this feature: choose Word 
Preferences, click the View tab, uncheck the Live Word Count box, and click the OK button.
If that doesn't help, choose Word Preferences again, click the General tab, uncheck the "WYSIWYG font and style menus" box, and click the OK button. This makes Word display the Font menu and the Style menu using system fonts rather than the actual fonts. It doesn't sound like much, but if your Mac has a ton of fonts installed, it can make a noticeable performance difference.
Still no good? Choose Word Preferences a third time, click the Spelling and Grammar tab, and clear both the "Check spelling as you type" box and the "Check grammar as you type" box. Both of these options chew up more processor cycles than they deserve.