When will people realise this will chance the whole mechanic of the game, and not the pretty effects?!
The graphics will display what the PhysX is calculting.
There is absolutely NO WAY the graphics card could render the full collapse of a building, brick by brick on its own. It will however display this on screen, but all the calculations of the bricks falling, the direction of the dust, possible fires will be done by the PhysX. Your graphics card will then use this data and render it in 3D with all its fancy shader and particle effects. This will lead to prettier games, but a lower rance graphics card could display exactally the same information, just without the fancy effects. But the underlaying collapse of the building will remain the same on both.
It means that instead of set explosions and completely scripted damage (stuff that at the moment would be impossible with the current level of physics calculation) that we will get extremely realistic that our PC's can generate on the fly.
Come on, next time you set a grenade off in COD or Quake 4, wouldnt you like to see some real damage cause by it (like broken pipes, falling bricks, prehaps a total collapse of a building and damage to the surrounding area, instead of just a puff of smoke and maybe a black mark on the wall for the next 30 seconds?