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. ...
If the problem is mostly at night and in unlit rooms, that explains why I haven't noticed it. I have my game well lit so I can see and I keep everything lit up, even at night.