As of version 4.15, Unreal Engine supports NVIDIA's Alternate Frame Rendering (AFR) for packaged games running on NVIDIA SLI configurations. AFR works by alternating frames between the linked GPUs; one frame is rendered by GPU 1, then the next frame is rendered by GPU 2, then back to GPU 1, and so on. By using multiple GPUs on a single monitor, its output can increase in image quality and performance!
Developers who intend to use AFR will still need to work directly with NVIDIA to test their games and to have it automatically switch over to use the Alternating Frame Rendering functionality where appropriate.
For additional details, you can read NVIDIA's documentation on their SLI modes, specifically Alternate Frame Rendering here.
Force Enabling AFR
For some applications, the NVIDIA Control Panel enables you to add a program for which the SLI Rendering mode will have AFR forcibly enabled. To do this, follow these steps:
- Open the NVIDIA Control Panel from your task tray, then navigate to Manage 3D Settings.
- Click on the Program Settings tab, then under Select a program to cumstomize use the drop-down to select a program to add.
- Next to the option for SLI Rendering Mode, you can select Force Alternate Frame Rendering.
This feature is not guaranteed to improve the quality or performance of your application and is not intended for use with the Unreal Engine 4 Editor. It is recommended to talk directly with NVIDIA to set up this functionality with their own driver.