After about an hour or two of play when I go to load a new cell, either by going into a building, going to a different interior part, fast travel, etc the game will lock up at the loading screen. The hints still change and the loading 'bullseye' is still animated but I wait about 5 minutes or so and it's still 'loading'. System should be able to handle it, Windows 7 x64, 16gb of DDR3, AMD Phenom X6 1045T processor, and plenty of drive space. Steam is even installed on it's own HDD.