Mozilla plans to enable WebRender in Firefox 92

Mozilla plans to enable WebRender in Firefox 92 for all supported operating systems and device types. WebRender is already enabled on Mac OS X (since Firefox 84) and on most Linux distributions (since Firefox 91). Starting with the release of Firefox 92, WebRender will also be enabled in Firefox for Windows and for Android.

The main idea behind WebRender is to improve the rendering of web pages by making the experience faster and smoother. Developed in Rust, WebRender has been in development and testing for a long time.

I wrote a guide in 2020 that explained how to find out if Firefox uses WebRender to render webpages. You can check it out to see if your copy of Firefox has the feature enabled already; here is just the short summary in case you are in a hurry:

1. Load about:support in the Firefox address bar.
2. Scroll down to the Graphics section.
3. Check if the Compositing value is set to WebRender.

Tip: you may also press Ctrl-F while on the page to search for WebRender.

WebRender may use hardware acceleration for rendering if supported by the graphics processing unit of the device. Software emulation is used if the GPU is not supported.

WebRender can't be disabled anymore in Firefox 93

From Firefox 93 onward, Firefox users can't disable WebRender anymore as options to do so are no longer included in that version of the web browser. The only option that Firefox users have when they encounter rendering issues is to switch WebRender to software.

Some configurations may never get hardware WebRender, e.g. if the hardware is too old or if drivers have bugs or issues.

1. Load about:config in the Firefox address bar.
2. Confirm that you will be careful if the warning page is displayed.
3. Search for gfx.webrender.software.
   1. Set this value to TRUE to enable software WebRender.
   2. Set this value to FALSE to disable software WebRender. Note that you can't force the use of hardware WebRender if the hardware/driver is not compatible.
4. Restart the Firefox web browser.

Linux users may want to check whether gfx.x11-egl.force-enabled is enabled, and set it to True of it is not. It should always improve performance, unlike WebRender on its own, which may sometimes cause performance to degrade depending on the graphics unit and driver.

Firefox 92 will be released on September 7, 2021 officially.

Mozilla plans to enable WebRender in Firefox 92