How to find out if WebRender is enabled in Firefox, and how to enable it if it is not

[harlan4096]

If you have used the Firefox web browser for some time and followed its development, you may have noticed the term WebRender being used occasionally in Firefox release notes. Mozilla published a technical and detailed explanation of its WebRender plans in 2017, and it is a good start to get a basic understanding of what WebRender is and how it is designed to improve the performance of the Firefox web browser.

The organization ran a WebRender study in Firefox Nightly in 2018. WebRender is designed to improve the performance of the rendering process in Firefox. It uses the GPU, the graphics processing unit, for that if available, but may also use the CPU if that is not possible. Mozilla started to roll out WebRender for certain configurations some time ago, but it is not obvious if the technology is enabled, and whether it uses the hardware or software acceleration.

In this guide, I'm going to show you how to find out if WebRender is enabled, if hardware or software rendering is used, and how to enable the functionality in Firefox.

Find out if WebRender is enabled in Firefox

Your first option is to use the troubleshooting page of the Firefox web browser. Here is how that is done:

1. Load aboutupport in the Firefox address bar.
   
2. Scroll down to the features section and check the value of the field "Compositing". If you see WebRender, you know that it is enabled in the browser.
   

Using about:config

What if you want to enable or disable WebRender, or check if hardware acceleration or the software renderer is used?

1. Load about:config in the Firefox address bar.
   
2. Confirm that you will be careful if the warning page is displayed.
   
3. Use the search field to find the following preferences, and to modify them once they are displayed:
   • gfx.webrender.all -- Set this to TRUE to enable WebRender, or to FALSE to disable it.
     
   • gfx.webrender.software -- This preferences determines if the CPU is used. If this is set to TRUE, WebRender will use the CPU, if set to FALSE, it will use the GPU but only if the GPU is capable.
     
4. Restart the Firefox web browser.
   

To sum it up:

• If gfx.webrender.all is set to FALSE, WebRender is disabled.
  
• If gfx.webrender.all is set to TRUE and gfx.webrender.software is set to FALSE, WebRender uses hardware acceleration.
  
• If gfx.webrender.all is set to TRUE and gfx.webrender.software is set to TRUE, WebRender uses the CPU and not the GPU.
  

Closing Words

You may want to test different configurations to find out which works best for you. WebRender is not yet available for all hardware configurations and systems; you can check out Mozilla's Wiki page on the status of WebRender.

Now You: Is WebRender enabled on your system?
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