from the specs you listed, your computer should run rome like an ethiopian runs a marathon.

the dxdiag seems the way to go. i was experiencing choppiness, particularly during the main menu screen, and other assorted unpleasantries, w/ a much lower-end system than your own, and here's what i'd recommend, have a huge crash, something which will give you an error report. it happened to me, i sent the error report to microsoft and the next day i got an update which fixed all my problems. rome is worth the effort.