Watt Usage Question

[Pepperlizard]

This question stems more from my lack of understanding of how a power supply works more than anything else. If all of the components in the computer that receive power from the power supply use say 650 watts but you are using a 850 watt power supply is more energy being used up by the computer than is needed to power everything in the machine or is the power supply able to output only the amount of power that is needed?

 

[StrangleHold]

Regardless the size of the power supply, the system only pulls as much as needed.

 

[Christian Darrall]

i had a 1000w running a pentium 3, its always best to have more power then needed so it doesnt stress the power supply

 

[spirit]

i had a 1000w running a pentium 3, its always best to have more power then needed so it doesnt stress the power supply

It's true that it's a good idea to give yourself a bit of headroom when it comes to power supplies (maybe 50-100W of headroom), but it's just a waste of money buying a 1000W or a higher-wattage power supply than what you require when you don't need it. You likely had nothing in your system which even required a power supply as large as 1000W and you probably have could have gotten with a much lower wattage power supply.