This section explains how to set up a multiple GPUs to effectively split both Viz Engines to individual GPUs. With Viz Engine version 5.3.0 and newer, multiple GPU capabilities have been implemented. 

Additional Hardware Requirements

In addition to the standard Hardware Requirements for the normal single GPU integration, a second GPU should be added.

• Minimum Requirements: 2x NVIDIA RTX A4000 (PCI 4.0x16 or higher)

• Recommended Requirements: 2x NVIDIA RTX A5000 (PCI 4.0x16 or higher)

Different GPU models of the same generation can be mixed, too, depending on the use case (for example, NVIDIA RTX 6000 Ada with RTX 4000 Ada).

Additional Software Requirements

• Viz Engine version 5.3.0 or newer.

• Unreal Engine version 5.3.2 or newer.

Activating Multi-GPU Support

To activate support for multiple GPUs inside Viz Engine with Unreal there are a few steps:

• Navigate to X:\ProgramData\vizrt\VizEngine\VizEngine-0.cfg. If you remove the second GPU from the system and want to return the integration to its single GPU pipeline, set the flag to 0.

• Search for the unreal_use_multi_gpu flag and set it to 1.

• Navigate to the installed Unreal Engine folder (should be under Program Files\Epic Games\UE_5.X), go to the \Engine\Config folder and open BaseEngine.ini.

• There, add the following command r.GraphicsAdapter=X (X being the gpu adapter you want for UnrealEngine), to the [/Script/Engine.RendererSettings] section.
  If Unreal is on the monitor's GPU, 0 is whichever GPU is connected there. If it is offscreen, 0 is GPU0. To return the integration to the single GPU pipeline, remove the command from BaseEngine.ini. Alternatively if the above command is not working for you, the following flag can also be set on the launch options -graphicsadapter=X

• Launch Viz Engine with the command -GX (where X is the GPU number. This can be checked on NVIDIA inspector and task manager). When in doubt, use NVIDIA inspector to see if the GPU load is correct (as in, if there is movement on both GPUs as that would indicate that Unreal is on one GPU and Viz on another). Typically, the first GPU is -G1 and the second GPU is -G2.

• The simplest possible configuration to use would be having Unreal just use the default GPU it wants and setting the GPU flag only on the Viz Engine side.

• An example of a simple configuration would be: Lenovo P620 with 2x NVIDIA A5000 GPUs, Unreal Engine set to use the first GPU and Viz Engine set to use the second GPU with the -G2 flag.

• To make sure the multi GPU integration is correctly splitting both Engines to each GPU, the NVIDIA GPU Utilization utility on the NVIDIA Control Panel can be used;