Hi,
Not sure about the EFI as I'm avoiding it as the plague, but on Intel platforms there are some issues regarding power consumption. Here's what I do: http://www.nux.ro/archive/2012/10/EL6_power_usage_optimisation_on_Intel_Sand...
that article looks quite out of date, tuned for example will handle quite a few things - and powertop can be used to tune accessories up as well.
Depends on what one is tuning for.
eg. i dont need the wwan interface most of the time, so loading the driver and powering it down is more productive than what most people do : dont load the driver till its needed