Originally Posted by Toss3
I get what you are saying and definitely wouldn't mind getting an extra physx card if there was a game that required it(/made proper use of it). Sadly this is not the case.
What I think is going on is that nvidia knows that a single GPU running both physics and rendering wouldn't outperform a multicore CPU + GPU doing the same task(fluidmark proves this, see chart below). They also know that most people wouldn't shell out for an extra card unless there are games out there that make use of it(reason why I think ageia would have failed). So they gimped the cpu support of physx to make having a physx-capable card look more attractive. It's marketing and makes them money they otherwise wouldn't get, but unless you own nvidia stock this is not behavior you should support as it hurts the consumer.
And yet you fail to address the point that GPU based Physics, when used soley for that purpose, totally out classes what any multi core CPU can hope to do.