Your profile indicates you're already using Office 2013 on Windows 8. What configuration are you running those in and on what hardware?

In any event, the biggest bottleneck in file saving has little to do with CPU speed or how much RAM you've got, but with drive you're saving to and how fragmented it is. Some drives also perform better than others - it's not really a matter of size.

As for what happens when editing (making changes), say, a Word document, that can be affected by your display driver, printer driver, the amount of graphics in the document, whether you're using Draft view or Print Layout view, have Word configured to display document graphics, and do on.

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Cheers,
Paul Edstein
[Fmr MS MVP - Word]