I used the GeForce experience app and had it optimise the game, so the frame rates no longer go above 200, but still seem to drop low very often, to around 30. But it's still random about responding to the keyboard, though the mouse movement is now very smooth.
@AmyPhoenix13 GFE's optimization has never worked particularly well with Sims 3, and I'd always prefer to manually apply the changes in the Control Panel or another tool instead. But if it's working for you, fine; just keep in mind that it might cause problems later. Framerate drops are not uncommon in TS3, although it's difficult to tell whether yours are just the game being difficult or something about yoru GFE settings.
Since the keyboard isn't responding consistently, I'd still test with a wired model if you can borrow one.
