Upgrading my PC

fingerinajar  Sims 4 shouldn't be lagging at all on this computer, at least beyond how it lags on any system.  Do you use mods or custom content, and if so, does the lag go away if you remove your Mods folder?  You don't need to save; this would only be for testing.

Please also try a different lot in a different world in this save, and a new save too, for comparison's sake.  I'm wondering whether the problem is the lot or save.

Even if you just want to upgrade, what to do depends in part on what kind of lag you're seeing.  So please let me know what you mean: fps drops, stutter, a delay in the game responding after you click, etc.