How can I make my cycles render faster? That is the question in every Blender artist and animator’s mind. We’ll look at a couple of methods for making cycles render quicker while still producing clean renderings.
NB: If you are looking for ways to speed up the new Cycles X render engine, go through the following tips ‘How to speed up Blender’s Cycles X rendering’
1. Optimize your sampling and denoising settings
The following are the Blender sampling settings that I use on my projects by default. They not only produce clean renders, but they also cut my render times in half.
- Go to Properties Editor > Render Properties > Sampling tab
- Set ‘Render’ to between 128 and 200
- Set ‘Viewport’ to 32
- Activate ‘Adaptive Sampling’ by checking the box
- Set ‘Noise Threshold’ to 0.01
- St ‘Min Samples’ to 0
- Under ‘Denoising’ subtab, activate ‘Render’ by checking the box and set it to ‘Optix’. Activate ‘Viewport’ and set it to ‘Optix’
- ‘Start Sample’ set to 0
- Go to the ‘Advanced’ subtab. Set ‘Seed’ to 0 and click the clock icon
- If you do not have any transparent material in your scene, set the Min Light Bounces, Min Transparent Bounces and Light Threshold to 0,0 and 0.01 respectively
2. Optimize light path settings
The following are the Blender light path settings that I use on my projects by default. They not only produce clean renders, but they also cut my render times significantly. I adjust them slightly depending on the materials and light sources in a scene. But these work on most projects.
- Go to Properties Editor > Render Properties > Light Paths
- Total – 4, Diffuse – 3, Glossy – 3, Transparency – 3, Transmission – 3, Volume – 0
- Under ‘Clamping’, set the parameters as follows: Direct Light – 0.00, Indirect Light – 10.00
- Under ‘Caustics’ set ‘’Filter Glossy’ to 1.00. Activate both ‘Reflective’ and ‘Refractive’
3. Enable GPU rendering in Blender’s user preferences settings
GPU rendering allows you to use your graphics card instead of the CPU to render. This can speed up rendering because modern GPUs are built to handle a lot of number crunching. They do, however, have certain limits in producing complicated scenes due to relatively restricted memory, as well as difficulties with interaction when utilizing the same graphics card for display and rendering.
How to enable GPU rendering in Blender 2.79
- On the top left corner, click File > User Preferences
- On the popup, click System in the top right corner
- On the Bottom left, select CUDA and check the box to select your GPU
- Then Save user settings
How to enable GPU rendering in Blender version 2.9 and 3
- On the top left corner, click Edit and go down the tabs and click Preferences
- On the popup’s left menu, go down to System
- Choose CUDA on the top menu and then check to select your GPU
4. Optimize your render tile size
Changing the “Tile Size” is another way to reduce render times. What exactly are tiles? Tiles are the small boxes that appear on your screen as Blender renders. Tiles allow the processor to focus on a smaller portion of the scene while saving memory, resulting in fewer or no crashes.
Surprisingly, the fastest CPU render time is also the slowest on the GPU. This is because the GPU can only render one tile at a time and thus does not benefit from more tiles. To summarize, the best tile size for GPU is 256 x 256. It’s 16 x 16 for the CPU. If those don’t work, try keeping it in the power of twos (e.g. 128, 256, 512, 1024), as the processor handles these faster. Below is a guide on how to change Tile Size in Blender.
How to change tile size in Blender 2.79
Under render properties, go to the Performance Tab
How to change tile size in Blender 2.9
Activate the ‘Auto Tile Size’ addon. Same as in Blender 2.79, under render properties, go to the Performance Tab. Copy the settings in the image below.
5. Activate the Persistent Data feature. Persistent Data is available from Blender 2.93 and above
Blender 2.93 got a major rendering update called Persistent data.
This is how it works: When you press the render button, your scene is calculated and cached on the first frame. The frames that follow rely on the first frame’s cached data. These can sometimes increase the speed of your renders by up to 5 times. Because elements in your scene are no longer calculated in every frame as they were previously.
Limitations of Persistent data
Persistent data performs best in static scenes. Scenes in which no objects are moving. An interior architectural rendering, for example. As of now, the Persistent data feature does not support caching animated objects in the scene.
Persistent data comes at a cost of increased memory usage.
How to activate Persistent data
Under render properties, go to the Performance Tab then the subtab ‘Final Render’
6. Optimize your HDRI multi-importance sampling
When working with high-res hdr environments, Blender can become very unresponsive when initially loading hdri. The reason for this is the time it takes to build an importance map that cycles needs in order to avoid fireflies during rendering. The importance map tells cycles where the bright areas of the hdri are so that it can favor those join rendering and produce a better result.
To optimize your hdri multi-importance sampling, go to the World settings > Settings tab. Change ‘Sampling’ from Auto to Manual. Now adjust the ‘Map Resolution’ value accordingly. You just need to set it high enough to avoid fireflies but low enough for Blender to respond incautiously. From my experience, values of 512 and 1024 work best for me.
7. Set a render region when working on shading or lighting of a single object
You can improve viewport rendering tremendously when shading or lighting a single object. Because cycles will concentrate all resources on the render region instead of the whole viewport. Since a selected render region is smaller than the viewport, cycles will render the region faster.
To select a render region, click Ctrl+B. Then with your mouse draw a box around the object you would like to view as rendered. Below is a .webp to help you select a render region in Blender.
8. Upgrade to Blender version 3 to render in Cycles X
What is Cycles X?
To put it simply, Cycles X is a collection of improvements for the Cycles render engine. The ‘X’ stands for the 10 years cycles render engine has been in existence. Users have reported Cycles X to be up to 30 times faster than its predecessor Cycles render engine. Of course, it depends on the scene settings.
Below is a graph comparison between Cycles in Blender 2.93 and Cycles X in Blender 3.0 on different test scenes by the Blender Foundation.
To use Cycles X render engine, you need to download and install Blender version 3. After installing, Blender will ask you if you would like to keep settings from your previous Blender version, which you should accept.
For tips on best render settings for Cycles X, read through ‘How to speed up Blender’s Cycles X rendering engine’
