Power Options in windows VISTA
There are three levels of preset power management in Vista … Balanced, Power Saver and High Performance … You can find further reading in this Microsoft Article. I personally recommend that you actually customise the settings other than relying on any of the presets. None of them is exactly perfect for most systems.
To customise these settings to your own needs, follow these steps.
Open power options by simply typing Power Options in the search bar from the start button. Or, go the long way and, click the Start button / Control Panel / Hardware & Sound / Power Options. ;-)
Click the “Create a power plan” in the left pane, I suggest using “High Performance” as the basis for our changes. You can give the plan a name if you wish or just leave the default.
Press Next to continue …
I suggest turning off the display after a set period of inactivity in time. This will have no impact on performance and really, it will not harm your monitor. Something around 15 to 20 mins should be fine.
I do NOT recommend enabling the “Put the computer to sleep” function, I’ll go into more details as we go along, for now, set it to Never.
Now press the Create button …
As you can see, we now have our new power plan ready to further tweak. Now simply click “Change plan settings” to get to the more detailed settings
… are we having fun yet ?
Click “Change advanced power settings” to continue …
source: pcreview