I recently upgraded to Word 2013 and have noticed that when changing the margins (dragging the margins on the ruler) that my CPU (i7-920 @ 3.5ghz) load will jump to 25%. This happens every time I drag the margins. This is especially noticeable because my CPU fan goes from inaudible to unpleasantly loud.
I can think of no reason why doing a simple things such as dragging margins should require such a ridiculous amount of CPU power. Any ideas what might be going on?