Sleeping tabs builds on the core of Chromium’s freezing technology. Freezing pauses a tab’s script timers, which minimizes CPU usage and frees up the operating system to reuse the memory for other open tabs, new tabs, or system applications.
What’s the difference between a sleeping tab and a discarded tab?
A sleeping tab simply pauses the page, allowing Microsoft Edge to release system resources. Specifically, sleeping reduces CPU usage to the bare minimum, which helps reduce battery consumption as well as release some of the memory. The advantage of sleeping a tab is that going back to it again is fast and seamless.
A discarded tab completely discards the page content from memory, allowing all of the resources (CPU, memory) to be released. The downside here is that when you go back to that tab, the page content needs to be fully reloaded.