After the latest patch this started happening to me slowly - on Barnacle Bay and Late Night. The other games are still fine SV, Riverview and Twinbrooks. I haven't been to China yet while playing Bridgeport but the choppiness/pausing in LN is getting unbearable. It happened in BB so I did start a new game-haven't played BB recently so I don't know how long it'll be before that choppiness/pausing starts or maybe it won't - but it did seem to become a bit hesitant last time I played with the moving around after playing it for a while. I'll get on that one again to see if it does the same.
I have a 2 month old iMac. Also a friend of mine that has a new iMac is having the same problem.
Both specs on both computers are more than enough to run Sims.
I did notice, which I think could be causing the choppiness and pausing, is that I have about 40 Sims that are all on Eugis Watering Hole lot and in the garage next door to it.
They are not going home or to their jobs, such as bar-tending, bouncers etc. No one is in the Nightclubs because they are all here.
They are all out there screaming, throwing up, fainting, going to the bathroom. etc.
I bulldozed Eugi's and now it's an empty lot, set no visitors allowed, I reset all the sims one by one and within a couple of minutes they all come back.
I also deleted the 4 cache files, dcbackup. That did not help either. Every time I start playing it's getting worse. I feel as though if I start another game, which I'm sure I'll have to if I want to play, sooner rather than later it's going to start doing this all over again.
I also do not use any mods. Only purchased items from the Sims 3 site.