Sleep Mode is a new browser extension for the Firefox web browser that hibernates all but the active tab on activation. Doing so frees up memory, saves battery, and may speed up operations.
Web browser users who open multiple tabs during browsing sessions may notice that memory use increases when doing so. Depending on the available resources, especially memory and battery, thresholds may be reached that may slow down operations.
Third-party tools and browser extensions may help tame memory usage of browsers automatically, semi-automatically or manually. Firefox lost a good chunk of extensions designed to improve memory usage as they relied on the old extensions system.
Sleep Mode is a simple extension that is highly beneficial in some cases. The extension adds an icon to the main Firefox toolbar during installation that you may interact with.
The icon acts as a toggle. A click starts sleep mode functionality. Any tab, with the exception of the active tab and tabs that have not loaded fully or not at all, are put into Sleep Mode to free up memory and improve power usage and performance of the system.
Sleep Mode unloads the site and adds Sleep Mode to the beginning of the page title; the latter may hide the entire page title which makes identification of the unloaded site difficult.
A quick test with just a few open tabs reduced memory usage by over 200 Megabytes (from 600 to 400).
Sleep Mode remains active and will put tabs with loaded content into an unloaded state automatically. Means: there is only one loaded site in Firefox when Sleep Mode is enabled. Note that the extension impacts pinned tabs and tabs with audio or video playback just like any other tab.
You may use an extension like Tab Suspender instead if you don't want pinned tabs or tabs with audio playback impacted by the suspension.
Another click on the Sleep Mode icon returns to normal mode. All unloaded sites are loaded again. You may need to switch to some tabs to complete the loading process. An option to limit the loading or prevent it from happening would be useful.
Sleep Mode is a useful browser extension for the Firefox web browser to reduce the browser's memory usage and power usage by limiting the number of active tabs in the browser to one. The unloading frees up memory, and if RAM usage is your main concern, it is certainly worth a try.
I'd like to see options added to the extension to improve usability. Options to ignore pinned tabs or tabs with audio playback, and more control when the mode is disabled would make a good start.
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