@Sharonia - Once you have your system set up you could also take a look at this guide to improve performance. I found there to be really good information and tips which help with game performance. https://steamcommunity.com/sharedfiles/filedetails/?id=1131162350. Remember to take backups before tweaking the files though.
Even if your game seems to be running well I'd personally recommend using some Nraas mods like Overwatch and Errortrap (+ MasterController). I just feel like they help with overall game health (and MasterController is my personal favorite) but each to their own.
I have a rig which, in theory, is more than capable of running TS3 but I still experienced lag due to poor optimization of the game and the amount of custom content. (From EPs I have Late Night, Seasons, Ambitions, University and Generations.) CAS especially lagged a lot but Nraas Master Controller setting for "compact view" does some wonders.
