As the first 2 replies stated, a waste of money. Croc said it was ahead of its time, but relative to CPU capability, it was behind. As THG review of the Ageia PhsyX Cell Factor demo shows here
http://www.tomshardware.com/2006/07/19/is_ageias_physx_failing/page3.html
the card is NOT required by the game itself, but rather, administratively...in short, a gimmick to sell unneeded hardware.
With todays multicore CPUs, an extra processing unit on a PCI slot is as useful as teats on a bull.
The below results illustrate tests of ageia phsyX. The tests show performance with and without the phsyX card. You can see theres not a lot of improvement. More importantly to gaming, where particle physics are concerned, is the fact that the tests are using reasonable GPUs but some older, less capable system components, i.e DDR400 and a single core CPU:
Processor(s)
AMD Athlon 64 FX-60
2.6 GHz, 1.0 GHz HTT Link, 1MB L2 cache
Platform Asus AN832-SLI Premium
NVIDIA nForce4 SLI, BIOS version 1205
RAM Corsair CMX1024-4400Pro
2x 1024 MB @ DDR400 (CL3.0-4-4-8)
Hard Drive Western Digital Raptor, WD1500ADFD
150 GB, 10,000 RPM 16 MB cache, SATA150
Networking On-Board nForce4 Gigabit Ethernet
Graphics Cards XFX GeForce 7950GX2,1 GB GDDR3
570 MHz Core clock
700 MHz Memory clock (1.4 GHz DDR)
PNY GeForce 7900 GTX, 512 MB GDDR3
675 MHz Core clock
820 MHz Memory clock (1.64 GHz DDR)
Connect3D Radeon X1900XTX, 512 MB GDDR3
650 MHz Core clock
775 MHz Memory clock (1.55 GHz DDR)
EVGA GeForce 6800GS CO SE, 256 MB GDDR3
450 MHz Core clock
525 MHz Memory clock (1.05 GHz DDR)
ATI Radeon X1900XTX, 256 MB GDDR3
520 MHz Core clock
540 MHz Memory clock (1.08 GHz DDR)
See the full article here:
Is Ageia's PhysX Failing?