Experiment = put the slider down a notch and see what result you get, and maybe try another notch down, and another..... I'm not promising anything, but sometimes this fixes slowdown problems. If that doesn't help, I really don't know what else. Video card drivers ? Maybe the expansion pack is too heavy on your machine ? Tell me how the original ran, was it really smooth or was that one having (lesser) problems too ? Expansion packs usually are harder on the machine than the original, because the developers add more eye candy and extra AI and stuff
