I got to the black market, and at some point there my game started to lag. I didn’t change any settings, and if I leave the area or make a new save file (in one of the other slots) the lag doesn’t go away.
I copied my save file and reinstalled the game. When I created a new game, it ran smoothly. But when I transferred my old save file, the lag returned. So I’m certain that the lag is coming from somewhere in the actual save file and not the game or my computer. Again, I didn’t change any settings. Anyone have any ideas or suggestions?