acsproductions Please delete Options.ini, inside Documents > Electronic Arts > The Sims 4, to reset your in-game options. Load a new save in Sunset Valley and see how it runs with the default options. You can change the in-game resolution and switch to windowed mode if you want, but don't change anything else for the first test.
If the game runs the way you want, exit to the Main Menu, change the graphics settings you'd like, quit to desktop, reload, and test again, still in Sunset Valley.
Please also let me know whether you've taken steps to limit your in-game framerates. If you have, double-check that the limit is being honored with the fps on cheat, which will put an fps counter in the upper-right corner of the screen.
If the new save still runs badly, please provide a dxdiag. Hit Windows key-R, enter dxdiag in the run box, wait for the scan to finish, click "Save all information," and save the file to your desktop. From there, you can attach it to a reply using the paper clip (Attachment) icon included with the other formatting buttons.
