BarTab Speeds Up Firefox, Loads Tabs On Demand - gHacks Tech News

BarTab Speeds Up Firefox, Loads Tabs On Demand

There are two situations in which the loading of tabs can slow down the performance of the web browser; During startup, if sessions are restored and a good amount of tabs need to be restored, and after selecting multiple websites to be opened at the same time, for instance by double-clicking on a bookmark folder.

The reason for the performance drop is simple. Web browsers like Firefox try to load all tabs at once, which increases the resource usage temporarily.

BarTab is a Firefox add-on that tries to resolve those issues by changing the default website loading behavior to on demand loading.

This basically means that tabs are only loaded when they become active for the first time. Only one tab is for instance loaded during system startup, all others remain inactive in the tab bar. This inactivity is indicated with transparency.

The same process applies if multiple websites are selected by the user to be loaded at once.

The browser extension can also unload tabs, to free up memory in the browser. A right-click on a tab displays two new context menu entries, to unload the selected tab or to unload all but the selected tab.

speed up firefox
speed up firefox

The options contain several settings to change the default behavior. It is for instance possible to add sites to a whitelist so that they are always loaded when opened.

It is furthermore possible to unload tabs automatically after inactivity, to reduce the memory usage of the browser.

BarTab can speed up Firefox by loading tabs on demand, and the option to automatically unload loaded tabs keeps the overall system resource usage on a lower level.

The add-on is directly available from the Mozilla Add-on repository over at


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  1. Paul(us) said on July 22, 2010 at 1:08 pm

    I use to work white this add-on from version 1.1 but main firefox browser crashed a lot, so i uninstalled it. But i will give this 2.0 version a new try because it’s a great idea

  2. Dever said on July 23, 2010 at 6:43 am

    As a person whos tab usage borders on abuse, I’m giving this extension a try. Thanks for the tip!

  3. Jojo said on July 25, 2010 at 8:19 am

    This is the best thing sliced bread!

    I typically have 45-60 tabs open at any one time. Many of them are things I want to get around to looking at but are just place holders.

    I usually have to shutdown FF and restart it up to 3-4 times daily because total memory used goes over 1GB and everything slows down significantly.

    When I complained to the FF forum, the replies told me that the problem was one or more add-on’s that I was using. Then they suggested enabling them one x one, which isn’t a workable solution in the real world.

    But now I have been running with Bartab enabled all day and I am only using 500MB of total memory so far. This is a great improvement!

    Virtual KB Curr = 508,608 Peak = 552,308
    Working Set KB Curr = 265,624 Peak = 312,176
    Page File KB Curr = 341,928 Peak = 397,796
    System Pool KB Paged = 257 Nonpaged = 70
    Private KB = 341,928

    Clearly, the problem is not with the add-on’s BUT instead, with either the gross number of tabs open or some specific tab that is racking up memory as it sits active and updates itself in the background.

    1. Martin said on July 25, 2010 at 10:50 am

      Jojo I agree, this add-on reduces the memory usage of the browser significantly.

  4. Thomas said on July 26, 2010 at 10:48 am

    Yeah, I use it too since a couple time, great add-on. recommended it already in an other topic about tabs.

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