Re: Will there be a 64-bit version of Sims 3 for Windows 10?
@AnnaBprp Please confirm in-game that your fps is limited to 60 (your screen's refresh rate) or whatever you intended to set. I haven't looked into the smooth patch's fps limiter—I still use the original version—so I don't know whether it works in all circumstances.
If that's not the issue, please try moving the household to a different lot, just as a test. Make it relatively simple, no clutter; it's a good idea to sell the furniture rather than taking it when the sims move, or else use Edit Town to evict them and place them elsewhere. You don't need to save your progress, or if you do want to save, use "save as" and rename it so your original doesn't get overwritten.
The method commonly cited to make Sims 3 use 4 GB RAM doesn't work and is unnecessary, as the game has been large-address aware since 2010. What this method does is change the size of the script heap, and its default is 20 GB (count the zeroes). We're not sure whether changing this value has an actual negative impact, but since it clearly doesn't help, it's best to undo that change.