The reason for a HDD is because Paradise needs to do a bunch of environment caching and streaming to make the online experience as buttery smooth as possible. But before you jump on EA's back for hiding such an important detail, know that that they didn't. It actually says, clear as day on the back of the box, that online multiplayer requires a HDD. So, no fault to them. We just wish Microsoft would mandate a giant "HDD Required for (insert word here)" sticker on the front of the game box. Though, we're sure Microsoft wouldn't want that either. It wouldn't be feng shui. Then again, no sticker would fix the "problem" that Burnout Paradise online play requires a HDD. Sorry Xbox Arcade owners, we feel for you.