Atomic needs a setting here it still remembers all the tabs you had open during last session, but doesn't automatically reload them all from the Internet when you launch the browser.
I'm all for this as I like leave a lot of tabs open for convenience.
It appears that Atomic currently reloads all tabs in parallel when it starts up and this can take quite a while over 3G. An option to load the current open tab before starting on the others would be nice.
No rhyme or reason to it. Sometimes it reloads, sometimes it doesn't. Would be great if it didn't in a future OS update. It happens when I'm on wifi or 3G.