Which is more efficent? why?

Which scenario would use more battery life?
Lets say with a 2 ghz processor

If is was underclocked to half speed, and I encoded a short video clip on battery, vs the processor going full speed on battery?

What uses moar power? why?

 

Scenario 2. Processor does not run underclocked.

Though I'm unsure with voltages, when a processor is undervolted all multiplier to a fixed number, let's say 0.950V in my T8100. If the highest multiplier is in use the same voltage is applied but it will generate more heat when in FID mode with the same voltage but no heat.

 

Full speed is more efficient. You must also remember that other components use power from the battery as well.

lets say the base computer sucks up 18 units of power per minute when on battery and doing nothing

encoding at half = 18+ 4 (for cpu) = 22 for 10 minutes = 220 units of power
encoding at full = 18+ 8 (for cpu) = 26 for 5 mins = 130 units of power

Honestly, I think my numbers are ridiculous, and worst of all, I can't remember the 'units of power' that I've read elsewhere.. there's a loong article about this somewhere here on NBR with charts and everything.

 

Less speed = takes more time to encode (this is not efficent)
Higher speed = goes quicker to encode as it's more efficent.
Takes less time to get something done

 

Thanks for clearing that up