Introducing Sleeping Tabs Experiment: Improving Memory Usage in Microsoft Edge


Note: We are in the process of deploying this feature, so it may be a little while before you see it in your respective channel and build.


To improve memory and CPU utilization of the browser, we've developed a feature called sleeping tabs.


Early internal testing of devices with sleeping tabs has shown a median memory usage reduction of 26% for Microsoft Edge. Our internal testing has also shown that a normal background tab uses 29% more CPU for Microsoft Edge than a sleeping tab. These resource savings should result in excellent battery savings. Although individual device performance varies depending on configuration and usage, we expect the decrease in resource and battery usage to create a better browsing experience for users.


Median memory usage of Microsoft Edge based on performance data aggregated across ~13000 devicesMedian memory usage of Microsoft Edge based on performance data aggregated across ~13000 devices


Average CPU usage of Microsoft Edge based on performance data aggregated across ~13000 devicesAverage CPU usage of Microsoft Edge based on performance data aggregated across ~13000 devices


Sleeping tabs builds upon the core of Chromium’s “freezing” technology. Freezing pauses a tab’s script timers to minimize resource usage. A sleeping tab resumes automatically when clicked, which is different than discarded tabs, which require the page to fully be reloaded.


We built upon the freezing technology to create sleeping tabs. This feature allows inactive background tabs to “go to sleep,” releasing system resources after a set amount of time. These resources include both memory and CPU and can be used for new or existing tabs or other applications running on your device.


By default, we’ve set tabs to go to sleep after two hours of inactivity. If two hours isn’t right for you, you can choose a different time interval in edge://settings/system. Tabs that are asleep will fade to let you know they’ve released resources. To resume a sleeping tab, click on it like a normal tab. The tab will un-fade and your content will be there immediately. You can also add sites you never want to sleep to a block list in Settings.

gif of several tabs open, with one fading to sleep, and 7 other tabs also fadinggif of several tabs open, with one fading to sleep, and 7 other tabs also fading

With this technology, it is possible that some sites may not work as expected after they go to sleep. We have built heuristics to detect these scenarios and prevent those tabs from sleeping to keep you in your flow. We are eager to get your feedback on sleeping tabs. If you experience a compat issue, please refresh the page and let us know through Microsoft Edge by pressing Shift+Alt+I on a Windows device or going to Settings and more … > Help and feedback > Send feedback.


Sleeping tabs will be coming soon to Canary and Dev Channels [87.0.649.0]. If you see the sleeping tabs feature while browsing, please join us here on the Microsoft Edge Insider forums or Twitter to discuss your experience, or send us your feedback through the browser! If you have any questions, see our FAQ or reach out to us. We hope you enjoy this exciting new feature and look forward to hearing from you!


- The Microsoft Edge Product Team



214 Replies
Absolutely amazing! I've been using it for a few days and I already love it so far! The only "issue" I've found with it is that it fails to puts some tabs to sleep even if they aren't relying on background activity. Still, I love this, thank you so much!



For those wanting to try it and do not see it in settings/system, go to "edge://flags" 

A Sleeping tabs  2020-09-24 071417.jpg

Type sleep in the search box...




Great features , I would like to add some feedbacks here:


1) Please set ability to enable or disable this feature in general from Settings


2) Ability to set disable or enable this in tabs by right click on them and select and it should show special icon.


3) Show specific icon for paused tabs

Great feature, good for devices with low RAM

Hi @Reza_Ameri-Archived, thank you so much for trying the feature. You can enable and disable the feature in general from Settings here: edge://settings/system. Do let us know if you have any questions around this, we're here to help!


Thank you for your feature suggestions. We are considering possibilities such as these, and your feedback is helpful. Looking forward to any future feedback you might have! 



Good suggestions.


I think it would be great to include/update:


- An option in settings that turns on or off the auto reload when the sleeping tab is selected. 

- A quicker way to exclude a tab from sleeping, rather than going to settings and pasting the URL in the exclusion area.

- I haven't had a chance to test if this exists but if a tab is closed, Edge should then select a tab that isn't sleeping instead of one that is. A new tab page should be opened if there is only a sleeping tab left after closing an active tab.


My current feelings:


- I do feel that changing the Favicon isn't necessary as the greyed out tabs are sufficient.

- Overall, I noticed an immediate rapid response of the browser when I enabled this and stopped using The Great Suspender extension.


I look forward to seeing how this evolves :D


Then that would be great and I believe they are manageable using Group Policy, Intune, Config Manager too.



I have sleeping tabs feature in Edge Dev Version 87.0.644.4, enabled it from flags.


there default timeout is too long, 2 hours.
it should be set to something like 30 mins.

another thing is that the minimum time we can set it to is 15 mins which is still long. I would like to set my inactive tabs to go to sleep after 5 mins or less.


now I know there is another flag to make this immediate (which means after 0mins) but I need something between 0 and 15, so please add more granular timers that are between 15 and 0 minutes.

thank you



Sleeping Tabs;

Ok, so, I've now tested each of the allotted times you all have listed as available for putting tabs to sleep. For each time I've waited to click the sleeping tab anywhere from between 0 to an hour. On each time I've clicked the sleeping tab, the response was an immediate responsiveness, and I could not see or notice any delay.


Personally, I cannot see a reason to have a 2-hour delay for putting tabs to sleep when the awakening time is immediately. It's not like you have to wait a minute or even 3 seconds for the tab to awaken as it is again, I say immediate. With that said I've chosen to use the immediate setting because of how quickly they awaken. Maybe you could put in an increment of 5 minutes between the 0 to 15-minute time for those that want shorter than 15 minutes, but not the immediate setting/flag.


Now there are sites that I've had lately with the last 3 or so canary updates that I have had to wait for tabs to respond. Sites like Facebook, Walmart, amazon and even this forum "WHEN" I've had 8+ tabs opened on each of those sites for various reasons. With this immediate sleep time I no longer have any delay. I LOVE THIS SLEEPING TABS!!!! I don't have Vertical tabs yet, so I am not able to test it with that feature to see if there is any difference, but I don't think there would be.


So all in all, this feature is Working Great for me on my system.
Kudos to the Team, Great Job!!





This is a much needed function, thank you.  I often have many tabs open that unnecessarily slow down my machine and use most of it's memory. 


For this feature, please include a right click tab menu item "Put tab to sleep' that changes to "Wake tab" after the tab has gone to sleep.  To wake the tab again user must either select 'Wake tab' from the right click menu, or hit refresh, or select another tab and come back to this tab.






... by the way, is there a way to force a tab into discarded mode which uses almost zero system resources?

No more right-click menu items please, there are way too many at the moment already, makes finding the option you want harder.

Strongly disagree.  The tab right click menu is sectioned off into 3 sections.  I don't have any trouble finding what I need.  The put tab to sleep item could go in the same section as Close tab which only has 3 items in it.  Are you using the right click menu so many times in rapid succession that you're getting slowed down by the number of items in it? 

Also please add menu item "Sleep tabs" when right clicking a selection of multiple tabs.

Too many right-click menu items already, long and crowded right-click menu is not helpful and slows down the usage.
there are way too many options already in the right-click on tabs that are not often used:

such as "add all tabs to favorite" - "refresh" (F5 button or the refresh icon next to address bar is more often used instead) - new tab (the + plus sign is more often used to open a new tab) - close tab (the X button next to each tab is more often used) - duplicate tab.

if they somehow get rid of those options, then fine, other than that nope, it'd be a regression to keep adding more option to the right-click menu that is rarely used by majority.

@sayjay09, thanks for giving this feature a try and sharing your thoughts around the experience - it's extremely helpful! Looking forward to any future feedback you might have!