A look at Microsoft Edge 87's Sleeping Tabs feature

Martin Brinkmann
Sep 19, 2020
Internet, Microsoft Edge

Microsoft plans to introduce a feature called Sleeping Tabs into the company's Microsoft Edge 87 web browser.The feature is designed to reduce the browser's resource usage by unloading background tabs automatically.

The feature is available as an experimental flag in the browser currently; you need Microsoft Edge 87 at least, which is currently available as a Canary channel version.

A total of three experimental flags are available that enable and customize the sleep mode of the browser:

  1. Load edge://flags in the browser's address bar.
  2. Search for sleep; Edge should return three flags.
    1. Enable Sleeping Tabs (edge://flags/#edge-sleeping-tabs) -- The main preference. Set it to enabled to enable the sleep mode functionality in the browser.
    2. Enable immediate timeout for Sleeping Tabs (edge://flags/#edge-sleeping-tabs-immediate-timeout) --The optional setting bypasses the timeout setting to put background tabs into sleep mode immediately. If you don't want background tabs to be disabled after a very short period, several seconds, keep it disabled.
    3. Sleeping Tabs use observed site characteristics heuristics (edge://flags/#edge-sleeping-tabs-site-characteristics) -- The optional setting enables heuristics to identify sites that should not be put to sleep mode, e.g. those with notifications or background tasks such as video or audio playback.
  3. Restart the Edge web browser.

Background tabs that are put to sleep use a light gray color of text to distinguish them from regular tabs that are not sleeping.

Hover over a tab to find out if it is sleeping. Edge displays "this tab is sleeping to save resources" if that is the case.

A click on the tab activates it again and restores it fully in the browser. The loading may take a bit longer if the tab is sleeping but it never took too long during tests. Mileage may vary depending on a number of parameters though.

The Sleeping Tabs feature is currently an experimental feature; this means that it may be introduced in a stable version of Microsoft Edge but that there is also the chance of it being pulled before it even reaches the stable version.

Firefox and Chrome users may use the Auto Tab Discard extension to unload tabs after a certain time of inactivity. The browsers support the automatic discarding of tabs, see our articles on Google's and Mozilla's implementation, but these unload tabs only in memory-critical situations.

Now You: Would you use a browser feature to unload background tabs automatically? (via Deskmodder)

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Microsoft plans to introduce a feature called Sleeping Tabs into the company's Microsoft Edge 87 web browser.
Microsoft plans to introduce a feature called Sleeping Tabs into the company's Microsoft Edge 87 web browser.
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  1. Haroon said on February 9, 2021 at 7:26 pm

    I found no difference in sleep and discard, why introduce something new when discarding is already there?

  2. chesscanoe said on September 20, 2020 at 2:43 am

    I would not use this feature because I prefer manual choice whether a tab simply should live or die. If I were more resource constrained (older PC) I would be more likely to use the described function.

  3. Anonymous said on September 20, 2020 at 1:26 am

    Does sleeping tabs cache the tabs, or do they require an auto refresh when waking up?

    1. Zol said on September 21, 2020 at 3:47 pm

      The restore is much faster (almost instant) than any discard/sleeper extension can do, most of the times you can’t even tell if the tab was sleeping or not before changing to it. Really well done.

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