Thanks for the suggestion, M.
Fez, I've been playing with the current settings for a while now: Very High Sim detail (due to some of the extremely high-textured hair styles I use), Medium Texture, Lighting and Shadows, and Visual Effects detail, and Low Tree detail and Draw Distance. I have only mirrors reflecting, the edge smoothing is off, and the number of high detail lots is 1.
I also have enable object hiding, animation smoothing, and advanced rendering on.
I'd like to keep my Sim detail at very high, as it has been since I received the game, but at the moment I'm willing to try anything.
Thanks.