I played it too. Built a city till 250.000 people and then quit the game. Even if you say it runs on two threads it still drops the fps rate when zooming in even just a little. And I feel the need to mention that I'm not using shadows, traffic and other visual options that might drop the fps rate. Well... all in all, I have only one thing to say: Bad management leads to bankruptcy in the end. Good luck, Focus!
Now I'm hoping that EA will make a new Sim City that is totally different than Deluxe.