I usually have many tabs open and that wasn't much of a problem before Firefox updated to Firefox Quantum and when the TabMix Plus AddOn was still working. However now Firefox has become barely usable for me mainly due to its RAM heavy session-restores which take a lot of time.

I tried a lot of things to solve this issue and read many posts about this problem online as a lot of people seem to have similar problems with Firefox Quantum. But it seems the only thing that really somewhat works with a large number of open tabs is the Tab Session Manager AddOn + the Tree Style Tab AddOn.

I hoped the Tab Session Manager AddOn would fix these issues in later versions, but it didn't: it still takes a lot of time to restore a session and Firefox still takes up a lot of RAM. (In addition the AddOn either crashes the browser or closes most of my tabs whenever it suddenly updates.)
I already disabled Supports Tree Style Tab and enabled Tab lazy loading in its options and have set browser.sessionstore.restore_on_demand, browser.sessionstore.restore_pinned_tabs_on_demand and browser.sessionstore.restore_tabs_lazily set to true in about:config.

When restoring a session it loads moz-extension://extension-id tabs with the extension-id as title and a loading animation as favicon. Running sudo tcpdump -X -s0 -w /tmp/browser_start and opening that file in wireshark shows that Firefox does a lot of requests when restoring a session. Whatever Firefox and the Tab Session Manager AddOn are doing when restoring a session: it takes way too much time and occupies too much RAM.

Is there any way / software to get the Firefox browser to reliably and quickly save and restore nothing but favicon, url and page title in session backups?

I wouldn't want to have it initiate any DNS-requests or reload the latest favicons or anything else and I don't see why it wouldn't be possible to have Firefox restore a session with hundreds of tabs including their cached favicons within seconds and with it taking up less than a gigabyte RAM.

Often people recommend just bookmarking tabs instead of having them open but I'd like my tabs to be shown as regular tabs until I close or bookmark them. (I don't see why having many tabs open should be problematic: in a world in which computer game graphics become increasingly indistinguishable from reality simply having a browser with many tabs open for research should certainly not overstrain a modern PC. All of this shouldn't even require AddOns.)

If that's currently not possible I'm interested in why that is. If Firefox itself really doesn't offer this capability I'm also interested in for example FOSS forks that do and links to relevant issues.

I'm running Debian 9 with KDE and am using Firefox-esr 60.3.

tl;dr: is there any way or software to get Firefox Quantum to save and restore nothing but favicon, url and page-title in session backups so that RAM-usage and session-restores take less time and RAM when having many open tabs?

  • Your question is very hard to get through. Much of it is commentary rant, and seemingly extraneous stuff. It contains a request for software recommendations, which is off-topic. It covers a lot of territory about things you want, which seems overly broad and ill-defined. In the end, it isn't clear how what you want isn't Firefox's default behavior. Can you rewrite this to just get to the point of the question and organize the critical information?
    – fixer1234
    Commented Nov 18, 2018 at 21:50
  • Thanks for the feedback: I improved it and also added a tl;dr. I wasn't sure whether this question would be better placed in softwarerecs. I decided to post it here because it's not just about software recommendations but also about tweaking one's system or Firefox and about e.g. code-issues in Firefox, Firefox-forks, and explanations. Basically if it's not possible to get this working in ff I'm interested in any technical and other information that would help with finding a way to get this working. For example whether the problem lies in the AddOn API and whether it is planned to get changed.
    – mYnDstrEAm
    Commented Nov 18, 2018 at 22:43
  • As near as I can tell, FF's default behavior is already essentially what you describe. If you want a massive number of tabs restored, it won't be instantaneous. But it does lazy, on-demand loading, so FF is usable pretty fast. I think the only other thing FF saves is the page status, which wouldn't really be a restore without it. Don't know if there's a setting to suppress that. The request for software recs is still off-topic. Much of the question is really a request that Mozilla redesign FF, and a justification for why it should be able to do better. Nobody here can do anything about that.
    – fixer1234
    Commented Nov 18, 2018 at 23:18
  • "Is there any way / software"...this is a software recommendation request which is off-topic here. Commented Nov 21, 2018 at 13:45
  • @TwistyImpersonator No necessarily. Maybe firefox can be tweaked so it loads only these 3 things from a file when restoring a session. Or maybe there's some issue on this already.
    – mYnDstrEAm
    Commented Nov 21, 2018 at 15:20

1 Answer 1


In Firefox 63, the discarded option for lazy loading is available in Tab Session Manager. Session restore performance will be greatly improved.

  • My understanding is that lazy loading is the default in Quantum, it hasn't been discarded.
    – fixer1234
    Commented Dec 12, 2018 at 2:41

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