Editing a document should not consume a CPU

Aah my old friend MS-Word. Today I had a document opened and was editing for my daughter. I had change marks turned on so that I could send her the edits and she could review it. I needed to move down a few lines in the document so rather than sliding the mouse I decided to move with the cursor keys. It took forever to move a few lines - I remembered that a while ago I had measured that moving the cursor in MS-Word with change marks on could peg one of my dual core CPUs. Truly amazing that user interaction can peg a CPU. I think it may be impossible to truly express my feelings for the state of MS-Office.