It's not lack of the patch - I installed that before trying the game the first time. I'm embarrassed not to have realized before, but it turns out to be a performance issue after all. I tried loading the tutorial again and walking away for a good 30 minutes. It had loaded when I came back. So much for my bravado about my new machine! I will continue reading the posts in the Apothecary and trying to optimize the game settings. Thanks, everyone.