A family of Microsoft word processing software products for creating web, email, and print documents.
I just want to stick my oar in and say that I too am getting this problem. I am astonished that MS has not addressed something as basic as this.
Incidentally, I don't think Skydrive has anything to do with it, since I do not use Skydrive and I am getting the same problem that has been described by other posters here.
Long documents in Word 2003 (which I was using prior to Word 2013) opened and saved in an instant. Furthermore, if you type fast, then the cursor speed lags so far behind your typing that it makes it almost impossible to work.
Like others, I have tried disabling various functions. This helps marginally, but only marginally. And reverting to .doc rather than .docx format helps, but this is not a proper solution either.
I still have Word 2003 installed, and have been reduced to using this if I want to work on very long documents.