EDIT: Does the 9600gso have 256MB dedicated graphics memory??NVIDIA SITE said:GeForce Driver v177.83 with PhysX support
This driver supports NVIDIAÂ® GeForceÂ® 8-series, 9-series, and 200-series desktop GPUs, including the newly released GeForce 9800 GTX+, 9800 GT, and 9500 GT GPUs. The driver adds support for NVIDIAÂ® PhysXâ„¢ acceleration on all GeForce 8-series, 9-series and 200-series GPUs with a minimum of 256MB dedicated graphics memory. NVIDIA PhysX System Software v8.08.01 is automatically installed with this driver package.