I've been in power/battery-constrained situations and it's crazy how much Chrome drains my battery compared to Safari. I still use it when I'm sure I'll be able to charge soon, but I've gone as far as converting some of my home-made extensions to Safari for situations where I need to conserve what I can.

Besides energy usage reported by the activity monitor, there is also the matter of how long the a user can stay on battery power. For laptop users, energy usage can be a huge deal for their overall satisfaction, even if the user isn't quite sure where they're gaining or losing anything.

The reason - Safari can delegate to linked in code that is allowed to take advantage of powersaving hooks in the OS, whereas, Chrome does the following: 1. Contact Google 2. Start to load page 3. Contact Google 4. Continue load page 5. Send more stuff to the big G 6. Maybe finish loading page 7. Why not send more stuff to Google