---
title: "Set Up GPU Rendering"
canonical: "https://documentation.chaos.com/space/VRAYHOUDINI/113279741/Set%20Up%20GPU%20Rendering"
format: markdown
---
After changing this option, you need to restart the V-Ray render server (if it is running) for the changes to take effect. If the V-Ray render server is running as a Windows service, you may need to stop it from the Services applet in the Control Panel.


## **Balancing the GPU Load**

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If you have only one GPU on your system, you may find that the user interface becomes sluggish and unresponsive while IPR is rendering on the GPU. To alleviate this problem, reduce the **Max. Paths Per Pixel** and/or **enable the Low GPU thread priority option** in the Rendering section of the **Renderer** > **IPR** tab of **[V-Ray Renderer](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113279154)** node. This breaks up the data passed to the GPU into smaller chunks so that the user interface requests can be processed faster. Note, however, that this reduces the rendering speed. Turn on the statistics display to check the difference in render speed and to find the optimal settings for your system.

> Macro (anchor)




## **Hybrid Rendering with CPUs and the CUDA Engine**

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V-Ray GPU can perform hybrid rendering with the CUDA engine utilizing both the CPU and NVIDIA GPUs. V-Ray can now execute the CUDA source on the CPU, as though the CPU was another CUDA device. To enable the hybrid rendering mode, simply enable the **C++/CPU** device from the list of CUDA devices.

The hybrid rendering mode does not require any special drivers. Furthermore, you can use the CPU as a CUDA device even if you don't have an NVIDIA GPU and/or NVIDIA drivers installed. Meaning, this mode can be used on computers that don't even have GPUs. The hybrid render engine running on a CPU [supports the same features](https://docs-chaos.atlassian.net/wiki/spaces/VRAYHOUDINI/pages/113279138) as the regular V-Ray GPU CUDA engine.

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## **References**

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- The NVIDIA CUDA developer zone: [https://developer.nvidia.com/category/zone/cuda-zone](https://developer.nvidia.com/category/zone/cuda-zone)
- For more information on hardware recommendations, see the [Hardware Recommendations](https://support.chaos.com/hc/en-us/articles/4406890478865-Hardware-Recommendations) article.