MrsFlynn,
I used a "Downloadable App to Help Game Run Better" in the stickied page Performance Issues in the Technical Help board. It seems to have helped at least a bit, I'm able to get maybe up to an hour's worth of smooth gameplay before it starts to stutter again, but it's better than having it immediately be in such a way. It's truly unfortunate having each expansion pack bog down the game more and more. I guess it just wasn't meant to be. But they probably should have stopped a great deal earlier with the expansion packs, hahaha
Seabody,
Well. OK. But also, this is good news to me. I was debating whether or not going into Sims 4 would be worth it or not, considering that I can hardly run Sims 3 in an enjoyable manner. But if it's due to the engine being... bad... to say the least... then I'll probably give it a go. Maybe immediately as I'm assuming little to no stuttering in that.
Anyways, thank you all for the replies. I guess my only option other than to stop playing The Sims 3 entirely is to play it until I get frustrated and transition into another game. Then come back, get frustrated, and transition again. Let's hope The Sims 4 will be fantastic!