I really wouldn’t go around using Skyrim as the example that Havok is good. Havok is good yeah, I dont deny that, but seriously, the number of glitches in Skyrim due to physics is right up there, everything from, all items in a room dropping a bit when entering a room, to things just spontaneously exploding when you enter a room, to the famous break dancing animals, and the list goes on.
In my project, I have thousands of physics objects (on the same level as Skyrim) and I am not seeing any of the above issues using PhysX, except maybe the occasional flying object, but I actually know why that is, sloppy placement on my behalf.