Utilizing a second GPU for PhysX in a multi-GPU system can significantly enhance your computer's performance, particularly in graphically intensive tasks. This guide provides a step-by-step approach to configure your NVIDIA Control Panel settings to use a second GPU for PhysX GPU acceleration.
Step 1: Accessing the NVIDIA Control Panel
Begin by opening the NVIDIA Control Panel. From the navigation tree pane under the '3D Settings', select 'Set multi-GPU and PhysX configuration' to access the relevant settings page.
Step 2: Configuring PhysX Settings
In the PhysX settings section, you'll find a processor list. Click on this list and select the NVIDIA GPU you wish to use for PhysX acceleration. There's also an 'auto-select' option, which allows the NVIDIA driver to automatically choose the best processor for PhysX tasks.
Step 3: Dedicating a GPU to PhysX
If your intention is to use the selected GPU exclusively for PhysX and not for multi-GPU rendering, there is an option to 'Dedicate to PhysX'. Check this box if you wish to reserve your chosen GPU for PhysX processing only.
Step 4: Understanding the GPU Configuration Visualizer
The GPU configuration visualizer is a handy tool that displays the pending PhysX configuration. 
It shows the active displays, their connection status, and indicates which GPU is designated for PhysX processing. A PhysX cloud symbol will point to the selected GPU, or if no pointer is present, it indicates that the CPU has been selected for PhysX processing.
Step 5: Selecting a Multi-GPU Configuration
Under the multi-GPU configuration, various options are available:
- 'Maximize 3D performance': This enables multi-GPU rendering for optimal 3D performance.
- 'Activate all displays': This activates all available displays and, where possible, enables multi-GPU rendering.
- 'Disable multi-GPU mode': Use this option to turn off multi-GPU rendering, which might be necessary for compatibility reasons with certain 3D programs.
The visualizer will also show the multi-GPU configuration, including which GPUs will collaborate for increased rendering performance.
Note: Impact of PhysX Dedication on Multi-GPU Settings
Be aware that if you've dedicated a GPU to PhysX, changing the multi-GPU configuration may reset this setting.
Step 6: Applying the Settings
After configuring your preferences, click 'Apply' to save the changes.
Step 7: Configuring Display Settings in Multi-GPU Mode
For systems with more than one display and multi-GPU mode enabled, the display settings can vary based on your Windows version and GPU series:
- Windows XP or Pre-GeForce 8 Series GPUs: You can select which display to use for your game. The 'Set up multiple displays' page allows you to choose the primary display for multi-GPU rendering.
- Windows Vista or Later, and GeForce 8+ Series GPUs: Choose the display to use as the multi-GPU focus display for full-screen applications on the 'Set up multiple displays' page. This display will receive full SLI acceleration.
If none of the displays in the multi-GPU group is set as the primary display, the driver will automatically select one for multi-GPU accelerated games. By following these steps, you can efficiently set up a second GPU for PhysX in your multi-GPU system, enhancing your computer's graphical capabilities and overall performance.