well, recently ive gotten a new pc, and when i played fleetops, it was fine at first, but as i began building more stations, it got jumpier. my theory is that the station models are lagging it out more because of the shuttles, perhaps less shuttles or no shuttles at all would increase performance. just thought you'd like to know..
btw, system specs:
p4 2.8
512 ram
radeon 9200SE 128mb