The closest extension that can save the open tabs into a list is [Sessions](http://dl.dropboxusercontent.com/u/8247646/sessions/index.html "Sessions by David Yoo").

You can also restore all the tabs all at once, or by double-clicking them to restore individual tabs.

Generally, after you save the tabs into list, you can close the rest of the tabs with <kbd>Option</kbd>+<kbd>Command</kbd>+<kbd>W</kbd>. Closing these tabs will free the memory that the tabs has taken. Meanwhile, your saved list of of tabs are stored in a document that won’t need memory to stay in use. The only time you’ll see the memory usage is when the Session extension is called (which get loaded with the list of the sessions you’ve saved).

Here is the comparison of the memory usage before and after all tabs are closed.

**Before**
![Session Before Closing Tabs][1]


**After**
![Session After Closing Tabs][2]


  [1]: https://i.sstatic.net/2bxxe.jpg
  [2]: https://i.sstatic.net/RCpV2.jpg