I'm guessing it's related to this:http://forums.appleinsider.com/showt...threadid=62435
I would say no. An Intel machine won't be significantly faster than your dual core G5. Some software is just badly written for OS X.
If you wanted to run Word at a decent speed, the intel Mac would let you run Windows using some hack but then you'd be running Windows.
I'd say use another word processor like NeoOffice.