My IP runs pretty well.
Must add, I disable all options available, Only turn on the collection butterfly for a 'hint' + turn it off.
I always pause before going to map view, and had found most of the problems mentioned and repaired
them. [bath wrong way around, front doors not set correctly etc]
I made sure not to place any new lots at all, and played to level 10 in the Life guard career and got all
the islands unlocked.
I had no trouble with Hobarts, ran it to 5 stars and sold it.
I have no mods, and use the Map to the Stars at 3 am with my game on pause to see if anyone is stuck
then reset them with the first name last name.
Bridgeport runs smoothly for me too. Always has, as long as I pick up and put down the elevator in Aquarius, and fix a little problem on top of the stairs in the Prosper Room.
Maybe I'm just lucky, or maybe it pays to go in and check everything out from Edit town before launching a game.
I find it time well spent.