PSU usage

[eggmasher]

I was wondering about the power usage of a power supply.

Let's say there is a computer using 400 watts of power, but there is a 1000 watt power supply in the computer. Does the power supply draw 1000 watts of current? Or just the required?

On a 1000 watt power supply, is the maximum it supplies 1000 watts, but adjusts its self due to its current load?


I am curious because in my next build, i am thinking about getting a GPU and in a year SLI it. I'm gonna get an 850 watt PSU, but i don't want to use electricity i don't need.

 

[DJDeCiBeL]

A PSU will always only draw what is required, but a PSU that is WAY above and beyond what you need will be slightly less efficient at the lower wattage that you will be needing, meaning it'll pull slightly more wattage from the wall than a high efficiency lower wattage unit. It's not a huge difference, but it's a difference, nonetheless.