No. This is not a good Physx card because it has only 16 cores (SPs). Read Nvidia's own words below.
Which graphics cards can accelerate NVIDIA PhysX?
All GeForce 8 series graphics cards and above with at least 256MB of local onboard graphics memory and at least 32 cores will be able to accelerate NVIDIA PhysX. If you intend to use an NVIDIA supported graphics card as a dedicated Physx card, the other graphics cards in the system must also use an NVIDIA GPU.
The two bolded parts above are the basic minimum specification of a Physx card.
Beyond this, there is an additional consideration:- if your main card is a top end card, you will need more than this minimum requirement. As the Youtube video shows, if your main card is a GTX580, the 8600GTS (with the minimum 32 cores) is not helping much.
Now, considering your main card is a GTS250, a card with 48 shaders will do some contribution as a Physx card but I think you better use a card with 64 shaders. Of course, if you move up to a card with 96 shaders, it most certainly will excel as a Physx card.
The cheapest card with 96 shaders that I can find:- Sparkle GT240 for US$35
Edited by windfire - 12/23/11 at 5:51pm