The Firefox web browser is still perceived by many as a RAM eater and a program that pushes RAM usage on many configurations to the limit.
When you analyze that you may come to a different conclusion though. Lifehacker recently ran some - limited and non scientific - tests with the result that Chrome and Internet Explorer used both more RAM than Firefox.
The developers of Firefox have started to implement features in the browser to improve its memory usage and performance. Among the features introduced is one that prevents the loading of all tabs during session restore on browser start up. This can speed up browser start up considerable and reduce the initial RAM use as well.
A very similar feature is planned for upcoming Firefox versions. The developers plan to integrate a feature into the browser that unloads tabs in the browser after an inactivity period. This would free up memory but also mean that it would take longer to activate the tab again.
If you are like me you have some websites open in tabs for safe keeping. Sites that you do not want to add to your bookmarks. I do that a lot for sites or software that I want to write about.
The Firefox add-on Dormancy adds the future Firefox feature to current versions of the browser. The developer states that it should be considered an experimental add-on that could cause issues on some systems.
The add-on unloads tabs after five minutes of inactivity. Firefox users can change the interval in the Firefox about:config configuration, which is a highly unusual place for configuration modifications.
The extensions.dormancy.TabDormancyAgeMs preference defines the time tabs need to be inactive to be unloaded, the preference extensions.dormancy.TabCheckIntervalMs the checking interval. Both values are set to five minutes by default.
The tab title of all unloaded tabs begins with data: so that it is always clear which tabs have been unloaded and which are still active.
The extension works considerably well. Users may experience small lags from time to time. This happened infrequently on my Windows test system.
How beneficial is the add-on? Firefox with nine active tabs and a handful of add-ons used about 280 Megabytes of RAM on the test system. With three tabs unloaded this dropped to 262 Megabytes. The gain obviously depends largely on the contents of those tabs The strange thing though is that you won't always see a gain, or reduction in RAM to be precise. It is usually easier to restart the browser for a larger reduction of RAM use by the web browser.
The second issue that I have with the add-on is that it adds a feature to the browser that is going to be implemented natively at one point in time. If you are desperate and need RAM it might be worth a try, if not it is probably better to wait until it is implemented natively.
Firefox users can download the Dormancy add-on from the official Mozilla Firefox add-on repository.
Update: Dormancy is no longer compatible with recent versions of Firefox due to changes made by Mozilla to the browser.
You can use an extension like UnloadTab instead which offers similar functionality and is still compatible with all recent versions of the browser.
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Ghacks is a technology news blog that was founded in 2005 by Martin Brinkmann. It has since then become one of the most popular tech news sites on the Internet with five authors and regular contributions from freelance writers.