Do you remember this change that Mozilla added to Firefox version 8: Firefox doesn’t load all the tabs from the previous session on startup by default, it loads them when you visit them, in this a bug created 8 years ago to unload or discard tabs automatically when memory is running low, the news is that the bug has been fixed today and the performance improvement has been rolled out to Nightly and enabled by default.
The complaint we’ve heard from some users since the release of the Multi-process architecture (e10s) is that Firefox is consuming more memory, your system specs, installed extensions need to take into account for this. You should know, e10s also bringing stability, responsiveness and performance improvements, if you have system setup with less RAM, set the number of content processes to a number you are comfortable with and disable hardware acceleration.
Note: The screenshot above is for representation only. It was taken from an old article.
But the default action taken by Firefox also helps in a situation where you’re multitasking, like listening to music on one tab and working on another, and you have more numeric tabs open.
Firefox 67 to unload tabs when memory is low
What this means is that Firefox goes in and discards tabs in the following order when it detects that some memory is needed, the browser unloads
- first tabs not playing audio and not pinned
- Pinned tabs do not play audio
- tabs playing audio
Note that priority will be given to regular tabs first over pinned tabs.
When Firefox detects that there is not enough memory or open tabs are using more resources, it tries to discard some tabs to free up memory.
The change can be controlled by changing the preference value
browser. which is set to true in Nightly edition by default for now on Windows.