Best macbook batteries strategies to watch a movie stored on an external USB hard drive Which is the best strategy to save the batteries of your macbook pro, to watch a movie that is stored on an usb hard drive (powered by the macbook) ?

1) Plug the usb hard drive and watch the movie from it.

2) Copy the movie on the the macbook hard drive, unplug the usb harddrive and watch the movie?

I personally think the 2) is the best, but can't say I'm sure 100%
Number 2 would definitely conserve battery as the device wouldn't need to be constantly powered