Firefox Enables ‘Fission’ In Latest Nightly Build: Feature Resembling Google Chrome Will Improve Performance But Eat More RAM

Mozilla is actively testing several features that are aimed at improving user experience, stability, performance and reliability of Firefox web browser. Firefox Nightly version, version 69, now has the inclusion of ‘Fission’ activation (Discovered by Techdows). The feature is quite similar to the Google Chrome browser. Although Fission will significantly boost stability and performance, it will also consume more RAM.

Mozilla is working on changing Firefox’s current process model to improve performance, security, and stability of Firefox operations. To support the endeavor, the company introduced Project Fission, an evolutionary extension to the multi-process capabilities that were introduced way back in 2016. One of the most critical core changes that Fission brings to Mozilla Firefox is the isolation of cross-site iframe into its individual process. In other words, Project Fission, if activated in Firefox Nightly version 69, will force any cross-site iframe to be loaded in its own process. This means the iframe will effectively be separated from the main content process of the site that user is accessing.

Needless to add, this method of iframe isolation strongly resembles the methodology already adopted by Google Chrome. In fact, Firefox’s evolving architecture resembles that of Google Chrome. Google led the development and deployment of the process isolation technique in an effort to ensure the entire site remains operational and functional. Google introduced site isolation support in the company’s web browser in 2018. As expected, the feature had a strong positive impact on stability and security. However, the new feature eats up additional RAM to offer stability. According to Google, site isolation support caused a 20 percent increase in RAM usage.

Mozilla has confirmed that it is aware of the ramifications of deploying site isolation support or Project Fission. It noted that Firefox would use more processes than usual. This would invariably increase Firefox’s RAM usage and requirements. Mozilla has added that it is trying to minimize the impact of Project Fission. It is likely that Mozilla would deploy a few memory optimization techniques within Fission before the feature trickles down to the stable versions of Firefox. Mozilla is actively working on the memshrink project. The project is expected to undergo several changes and improvements which may or may not be implemented in the Firefox web browser.

How To Enable Project Fission in Mozilla Firefox:

Mozilla has included the ability to activate Project Fission within Firefox Nightly version, version 69. Firefox Nightly users can choose to enable Fission, but it is currently kept deactivated by default. Users are cautioned that both, Firefox Nightly versions as well as Fission, are experimental in nature. Users should expect a few bugs. Moreover, users could experience crashes when they visit sites and face other issues while they browse the Internet. In other words, users should use Firefox Nightly and Fission only for testing purposes.

Activating Fission is quite simple. Users need to enter about:config in the web browser’s address bar and accept the standard cautionary warning. Search for fission.autostart. Set the preference to Enabled to turn Fission on, or Disabled to turn it off. Restart the Firefox web browser to implement the changes.

To confirm Fission is up and running, users can visit the about:support page of the Firefox browser. They should see a new Remote Processes section on the page wherein there will be mention of open tabs and iframes. Most of the listings will have webisolated tags at the beginning. Windows Task Manager will also reveal that Firefox uses more processes than before. The quantum, of course, depends on the number of open tabs and sites that the user is accessing.

Firefox recently gained the ability to stop auto-playing videos. This feature has been welcomed by the majority of the users. There have been positive reports about the additional granular control that the browser is granting to its users. Moreover, with Google aggressively deprecating APIs that block ads before they are loaded, browsers like Firefox could soon gain several more users.


Alap Naik Desai

A B.Tech Plastics (UDCT) and a Windows enthusiast. Optimizing the OS, exploring software, searching and deploying solutions to strange and weird issues is Alap's main interest.