As I mentioned in an earlier post in the General forum, I don't think it make sense to target PPUs. The market's move towards multi-core processors solves the problem of needing added computational power to handle advanced physics capabilities. Why not target these CPUs instead of releasing proprietary hardware that contains a processor which would likely offer equal performance to a single core on a motherboard. I would hate to think that I could be running a game on a computer that has 4 cores, but only one of those would be used by that game because added physics effects require me to dish out $200 for yet another card with yet another processor.
The problem is further compounded by the fact that there isn't a open standard like OpenGL that allows manufacturers to create drivers with common interfaces, so that a game company can use common code to interact with multiple devices. What if the makers of Half-Life's Havok physics engine, or another company, role out thier own PPU. Will Sega's games work with it? Not likely. The APIs that interfaces to thier own hardware will not be the same. So does anyone believe that Sega, or other companies will spend added months writing more code just so that they can target every card possible?
The model of proprietary physics hardware can only succeed if one company manages to swallow up the whole market (in which case there is one device to target because that is the ONLY device). I like the idea of added physics, but the whole hardware thing makes me believe that this is going to blow up in the faces of those that market it for the PC.
I can however see it having success on the consoles though.
Suppose I could be wrong on all this though.