My games on the whole are ok, some crashes and graphics glitches but not too bad. The problems arrise when I load a saved game. Civ staggers into life and then falls over within 3 or 4 seconds every time. I can avoid this problem if I always start a new game with the same settings first. If I load my saved game from within the new game everything seems to be fine from that point on. I have completed several large and huge games using this approach. Hope this helps somebody. Just for the record I tend to play large maps.