Make the Sims age again? What is a workaround for this bug

It happens to me too, and ONLY at Shang Simla, no other place... I read around and the common conclusion is that a sim out there got stuck and can't find a right pathing to get out so it keeps running a check to find a correct pathing to get out of the stuck condition, which is why the game lag every few min (game time)... which makes sense since there are quite a few spots there where a sim can get stuck with the horrible pathing.
I use http://ts3.tscexchange.com/index.php?topic=4685.0 which seems to help, but like any CC it probably has some risks too

The Sims 3 is notorious for high CPU and resource usage, especially when you get multiple households and things going. Try opening up the task manage (ctrl+shift+esc) while playing and take a look at the CPU and Memory percentages. If they are pegged at 100% or close to it, that may be the problem.

The game does try to "optimize" by instead of the entire game chugging, only certain processes of it do, like sim behavior and the background world simulation (which is why everyone is tired). Something to try is lower the various settings, or removing households you don't really care about so the background simulation doesn't have to work as hard(backup your save in case this doesn't work!).