Hi....I just purchased and am waiting for delivery of my shiny new EVGA GTX 580.  I am upgrading from a GTX 285.  Would there be any benefit to using my 285 for Physx for games like Metro 2033 and Batman AA? I was reading on the Nvidia forums that using a dedicated Physx card with less than half the shader cores does not improve performance and can sometimes hurt FPS.  I just started playing Metro 2033 with my GTX 285 with an old 8800 GTS 320 Mb  for Physx and did not see any improvement in performance.  Thanks for any advice or recommendations.  

It's hardly overkill.  With a powerful Fermi setup like a GTX 580, you need a powerful card dedicated to PhysX to actually get a performance increase and the GTX 285 is plenty powerful.  Go for it if you need/want the performance boost.  When you're not playing PhysX games you can run a folding @ home client on it.

Thanks for the confirmation Boredgunner..  And as an added bonus I won't have to to put my heat on all winter in my apartment!  :-)

I have 1 580 on the way and trading in my EVGA 470 for another 580 for SLI.  I have my other 470 sitting around.  Considering using it as a Physx card...but, lol, no, no I think I'll just sell it.  Now THAT is overkill!