Mozilla slashes Firefox macOS power draw

Mozilla's Henrik Skupin has teased an upcoming update to the Firefox web browser which will cut its power draw by around a third on macOS devices - by switching to Apple's own Core Animation framework.

Launched in beta form back in September 2017, Firefox Quantum brought a much-needed speed boost to Mozilla's open-source web browser. Unfortunately for macOS users, it also brought with it considerably higher power demands - to the point where the browser would visibly drain a laptop's battery, resulting in considerably shorter runtimes than browsing the same sites using Apple's rival Safari browser.

Now, Mozilla's engineers believe they have finally solved the issue - by farming off the rendering part of the process onto Apple's Core Animation compositing framework. 'If you are running Firefox Nightly on macOS you will see a huge decrease of its power usage by a factor of about 3x,' claims Mozilla's Henrik Skupin of the change. 'E.g when loading web pages! It's all about making use of Core Animation for rendering now.'

The impact of switching to Core Animation is measurable: In the Bugzilla issue tracker, which opened a bug for the problem two years ago, one developer measured the 'tab throbber,' an animation which indicates a page is loading, as drawing 20W in power from the GPU and leaving the CPU starved for power prior to the switch, but now drawing less than 1W from the GPU and allowing the CPU to run considerably faster - 'miles faster as well as cooler.'

At present, the new Core Animation functionality is only available on the Firefox Nightly builds; it will come to the Beta branch next, and once thoroughly tested will be released to the general public. None of the changes impact other platforms, however, with Core Animation being an Apple exclusive feature.