Plugging in a external monitor to be the only display on a MBP requires clamshell mode (which is not a viable option for many; the MBP gets very hot).
So I have a hotkey set to dim the built-in display brightness to 0. This saves the backlight from being used; but the built-in display is still rendering.
Since there's no way to disable the display completely (except for clamshell mode), how can I further get close to as if the built-in display is turned off?
Which uses the least amount of resources? Having the built-in display be a mirror to the external, or serving as a extended screen?
I'm assuming the extended screen is less resource intensive as it requires the least amount of draw / render (nothing ever goes to it). Where as the mirror would probably do a lot of 'copying' over, it still has to render on a built-in display no being seen / used.
Update: Did a very quick test, 1080 video playback in full screen watching for frame drops, I get surprisingly a lot more in extended. Very minimal drops in mirror.