If you nabbed yourself a copy of Assassin's Creed 3 late last night (or later this morning, for all of us who got Sandy'ed last night), then you'll probably find a day-one patch waiting for you as soon as you fire it up. Ubisoft recommends downloading it before diving in -- as if your gaming console of choice would allow you to do any less! -- because of the many fixes it makes.
You can read the full patch notes at Ubi's forums, though beware that you'll see some spoilers there. Nothing huge, mind you, but enough that you might want to just avert your eyes and allow the patch to work its magic. The short, spoiler-free breakdown: things work better now than they did before.