8 points
The only time that would make a difference is if you’re staring at a blank page and the only thing causing the screen to update is the clock. Theoretically the GPU could go completely to sleep, except for having to draw the updated clock every second.
But there’s a reason battery life is commonly measured as “hours of video playback”. If the laptop’s not actually doing anything you may as well turn it off and get weeks of battery life.
