UPDATE 9-2-20 Has your Sims 3 game been affected by the recent pixilation issues?
UPDATE: 3/8/2021 Cororon has been affected now and is determined to figure this out, yaaay! Please go to her thread on Nvidia and support her efforts to have Nvidia take a look at what's going on. ...
I'm not sure about pixelization, but I got these weird shadow issues, too. I first noticed it on untextured walls, but yes, it's also seen on shiny surfaces like fridges.