Firefox 55 reduces startup time by 90 percent and memory usage by 75 percent
I'm a self-confessed serial browser user, and Firefox is one of my favorites (along with Vivaldi and Opera), which is why I have been particularly frustrated with the performance reduction it started suffering from around two years ago. Fortunately, this is likely to change from Firefox 55 which is currently in beta. Dietrich Ayala, a developer with Mozilla, ran a test of Firefox 20, 30, 40, and 50-56 using a profile containing a whopping total of 1961 tabs.
The first test was to measure how long it took each of those browser versions to start with the same tab profile selected. Wifi was disabled so that the test was measuring how long the browser took to load the profile, not how quickly Ayala's internet connection could download each of those pages. Firefox 54, the current version, took roughly four and a half minutes to load to a point where the program was responsive. Firefox 55 beta showed a massive reduction in load time taking only fifteen seconds to perform the same task.
Ayala's second test was to quantify if there was a change in RAM usage. The trend from before was repeated, with Firefox 54 using slightly over 2 GB of RAM, and Firefox 55 using slightly under 500 MB.
These performance improvements are attributed to "quantum flow", the name for the project with all the departments of the development team, such as UI or the Gecko rendering engine, working together to improve responsiveness and smoothness of the browser.
There are, of course, a couple of limitations of the test that must be mentioned. The first is that the web pages weren't rendered, and we would expect this to increase both the loading time and the amount of RAM used, but Firefox 55 should still retain the lead. The second limitation is that the test system was running MacOS and the Mac version of Firefox. While performance is likely to be similar between both the Windows and Mac version, there are definitely differences in the way the operating systems handle memory usage.
Even with those test limitations taken into account, this is a good sign of what to expect from the next Firefox browser.