The 'Sleeping Tabs' feature also helps to extend device battery life and thereby reducing its power consumption with the background tabs set to idle state. With early internal testing of sleeping tabs on devices showing a median memory usage reduction of about 26% for Edge browser. Microsoft's internal testing has also shown that a normal background tab uses 29% more CPU for Microsoft Edge than a sleeping tab.
Albeit, the individual device performance varies depending on the different configuration and usage, even as the decrease in resource and battery usage is expected to create a better browsing experience for users as well.
How the Sleeping Tabs leads to Reduction in CPU and RAM consumption
The Sleeping tabs feature builds upon the core of Chromium’s “freezing” technology which pauses a tab’s script timers to minimize resource usage.
While the tab resumes automatically once clicked, which is different from discarded tabs, that require the page to fully be reloaded to be live again. The feature simply allows inactive tabs in the background to “go to sleep,” thereby releasing system resources, which resources include the RAM and CPU necessary for other applications running on the device.
And the tabs are set to go to sleep after two hours of inactivity by default, which you can also choose a different time interval from edge://settings/system when the tabs will go to sleep. These tabs that are asleep fades to show that they’ve released some resources.
How to manually set timeout for Sleeping Tabs in Microsoft Edge
The Sleeping Tabs feature is now available on Edge Canary and Dev Channels (87.0.649.0), so you'll need to update your browser to take advantage of the new tabs functionality.
Once you've updated to the Edge Canary and Dev bulids, you’ll have to visit edge://flags/ and enable the three flags present, after which, you’ll find the Sleeping Tabs option on edge://settings/system, where you'll be able to tweak the tab timer and manually add sites that you don’t want to go to sleep while inactive.