Mactopia Product Forums: Excel 2008: Slow typing when using Parallels

Article here.

The subject and title of the page is a bit misleading in that the problem really seems to have nothing to do with Parallels, but the solution is right on:

If you are experiencing really slow typing performance (“slower than frozen snot”) in Excel 2008 for Macintosh and you have files in File>Open Recent Items… which are from a Windows network volume, then go to Excel>Preferences>General and disable Show this number of recent documents.

Performance should become snappy again.