It should provide a nice little bump in games that use GPU PhysX as it will allow your 480 to focus on rendering and the 8800GT to perform all the PhysX calculations.  The 8800GT is a great choice as a PhysX card because its single slot and doesn't use a lot of power.

here's a list of compatible GPU PhysX accelerated games, these are the titles that would benefit from the dedicated PhysX card. 
http://www.nzone.com/object/nzone_physxgames_home.html

BFBC2 doesn't use Physx? How is that possible?

vgerik1234

BFBC2 doesn't use Physx? How is that possible?

It uses software physics, Havok I believe, which are good, just not as good as hardware accelerated physics effects like GPU PhysX.
 

zschopf1

vitaminx

Wow... I thought there was more games then that supported =/   Thats not many at all.

 
That list only shows 1/10 of the actual games that have Physx capabilities, not including demos. Gears of War should be on there, Assassin's Creed, and many others. I'm not sure why that list is so small, but there are many games that infact use Physx.
Here is the actual list. http://www.nzone.com/object/nzone_physxgames_all.html

The list I linked accurately reflects the games that will benefit from GPU accelerated PhysX, which is what the OP requested.  The "All" list of PhysX titles linked there use the software PhysX SDK, which is similar to other software (CPU) accelerated SDK/libraries that have been available for years, like Havok. 
 
Also, AC1 and 2 are both Havok titles.

zschopf1

chizow

The list I linked accurately reflects the games that will benefit from GPU accelerated PhysX, which is what the OP requested.  The "All" list of PhysX titles linked there use the software PhysX SDK, which is similar to other software (CPU) accelerated SDK/libraries that have been available for years, like Havok. 
 
Also, AC1 and 2 are both Havok titles.

Before Ageia was bought out, many of these games were on their list that supported the use of their independent Physx cards. However since Nvidia bought them out, the software in which support Physx has grown. Xbox 360 and the PS3 both have the Physx cards integrated into their system. So anything you see on the list does indeed use Physx by Nvidia and the Physx chip on the Consoles. Whether the games stress the use of Physx or not will determine the appropirate need for a dedicated Physx card. I have had it in some cases where my 8800GT coupled with a GTX 295, suffered in a Physx supported game because the 8800GT's calculations could not keep up with the ability of the GTX 295 in SLI mode in games that where not Physx intentsive. In Physx intensive games I would notice a good 10-20 FPS increase from using the 8800GT as a dedicated Physx Card. It all depends on the game, you just need to find the G spot of the game if you know what I mean. =P 

The games and demos supported on the Ageia PPU are also supported by any PhysX capable GPU enabled after Nvidia bought out Ageia.  GRAW2, UT3 PhysX pack, Warmonger, etc, they're all there.  360 and PS3 are similar to the software accelerated PC titles in that they are simply running the PhysX binaries on their own CPUs, there is no additional acceleration beyond that as neither of those consoles have a dedicated PPU or a PhysX capable GPU.
 
So again, it should be very obvious, the "small list" is GPU/PPU (hardware) accelerated PhysX and the "big list" is CPU/Cell/Motorola/ARM/Tegra (software) accelerated PhysX.  They're very different in terms of capabilities and number of supported titles, and while the list of hardware accelerated PhysX list is still growing, its not anywhere close to 100% adoption like software physics (most any game uses some kind of physics simulation whether proprietary or licenses middleware).

zschopf1

chizow

The list I linked accurately reflects the games that will benefit from GPU accelerated PhysX, which is what the OP requested.  The "All" list of PhysX titles linked there use the software PhysX SDK, which is similar to other software (CPU) accelerated SDK/libraries that have been available for years, like Havok. 
 
Also, AC1 and 2 are both Havok titles.

Xbox 360 and the PS3 both have the Physx cards integrated into their system. So anything you see on the list does indeed use Physx by Nvidia and the Physx chip on the Consoles.

 
Don't confuse PhysX with Physics.  And don't confuse using the PhysX SDK with using a PhysX hardware accelerater.
 
Neither the XBOX or the PS3 use standalone PhysX hardware acceleration.  It should be obvious that the XBOX 360 doesn't considering that it using an ATI GPU.  Why would the XBOX 360's ATI GPU run NVIDIA's GPU PhysX?
 
+2 to Chizow.  The number of games which will benefit from a standalone PhysX accelerator are few and BFBC2 is not one of them.

I attempted this and actually got worse performance with the 8800GT as a physx card.

 
Out of curiosity, what test did you use to measure the PhysX performance and conclude that using a 8800GT was not worth it?
 
If you measure the performance difference using 3dmark vantage, be advised that the results will always favor the more powerful GPU regardless of which setup real-world PhysX gaming performance would best benefit from.  This is because 3dmark vantage runs the PhysX test while at a very low resolution and graphics detail.  This means that GPU rendering load is very low and the primary graphics card can focus pretty much solely on PhysX and doesn't have to spend much time on rendering.  On the other hand, in a real-world PhysX game environment, it may benefit you to place the PhysX computation load on another GPU even if it has lower overall raw performance than the primary rendering GPU solely to allow the primary rendering GPU to focus on rendering only.
 
That aside, it does seem plausible that a 8800GT would not be of much benefit as a PhysX GPU when paired with a "Fermi".
 
 

InnerDemon

fluidmark.

Copy.  Assuming that you ran the test at a realistically high resolution (not 640x480 or anything like that) and filtering, the results should be pretty reliable.