power saving on laptops

devizes18193

Hi ,
I can see using the power saving on a laptop will make battery usage last longer , but if its used on the mains are you using less electricty . My son says you are but Im not sure as surely the power supply is outputting the same voltage either way . What do you lot think

isofa

If the PSU on the mains is correctly regulated, then it'll only supply up to what is being drawn by the laptop. Less consumption from the laptop = less power supplied.

It's similar to the fallacy of leaving a mobile phone charger plugged in constantly costing you lots a year to run (and contributing lots of CO2 to the atmosphere!). As soon as the phone is disconnected from the charger, the output is virtually zero, even though it's still plugged into the mains.

devizes18193

isofa wrote: »

If the PSU on the mains is correctly regulated, then it'll only supply up to what is being drawn by the laptop. Less consumption from the laptop = less power supplied.

It's similar to the fallacy of leaving a mobile phone charger plugged in constantly costing you lots a year to run (and contributing lots of CO2 to the atmosphere!). As soon as the phone is disconnected from the charger, the output is virtually zero, even though it's still plugged into the mains.

The child was right "dam he will enjoy this ". thanks

Poppycat

Well it depends. It normally no more power than via battery unless you have it set up that way in the power management.

For example when mine is on battery I have the screen brightness turned down by default. As soon as power from the main the brightness increases so thus draws more power from the mains than it would via battery.

Of course you could equally have power management turned off and it would draw the same power as it would via mains or set power management so it draws less power from main, ie cpu cycles, LCD brightness etc