Anything concerning sims seem to be delayed on lots with large amount of sims on Speed 3.

Moar investigating! It seems that "scheduling.simulate" is running too slowly. I've changed the function which calls it to log to a file if the Sim Timeline slows down. And it slows down, a lot! Even on speed one, there are quite a few messages on the lag. Here's a log that contains every time Sim Timeline lagged on Speed 3.pastebin.com/vWzBrKDn