Mozilla developer Dietrich Ayala has put together some impressive charts to show huge improvements in memory usage and some performance metrics in Firefox. Much of the impressive new pep he observed is thanks to a project called Quantum Flow which targets changes that directly impact Firefox responsiveness. If you are a 'pathological tab hoarder' the news of improvements delivered in Firefox 55 and 56 will be particularly appealing.
Mr Ayala could be called an extreme user of Firefox and has been working for Mozilla for over a decade. His default browser profile means that when Firefox loads it loads with 1691 tabs. In previous versions of Firefox, including recent ones that usually means a startup time of 5 minutes or more on Ayala's Macbook computer.
The worst performer looks to have been Firefox 50, which took almost 8 minutes to start up and become responsive with the 1691 tab user profile. Recently in versions 52, 53, and the current mainstream Fx54 things have improved to under five minutes. However there's a massive reduction in startup time seen with FX55 and 56 versions.
Check out the chart above to get an overview of the massive change delivered by Mozilla's Quantum Flow technology. Work done by Kevin Jones, Dão Gottwald, Mike de Boer, Tim Taubert, David Teller, Mike Conley, and Gijs Kruitbosch is behind these improvements. The team are trying to get "the overall cost of unloaded tabs as close to zero as possible".
If you have a memory limited system such as a netbook or tablet, Firefox might not have been a good choice previously, especially as a 'tab hoarder'. With Fx55 and 56, and the same 1691 tabs open, memory usage after startup is reduced significantly. In the chart below you can see the Quantum Flow optimised app uses up under half a GB of RAM while older modern versions would easily consume 2GB plus.
At the time of writing Firefox 54 is the current non-beta version of the browser and doesn't provide the above tab hoarder performance and memory benefits.