Quick question about PSUs..

[ehcastro3]

Sup guys...

If my rig requires about 600 watts, then I get a 1000w PSU, will the PSU get 600w or the whole 1000w from my wall socket?

If its 1000w, then I should stick to a PSU that is about 700w right? To save $ from the electric bills?


TIA

 

[amnotanoobie]

It will only get what it needs from the PSU. Most PSU's efficiency are the highest at around 40~60% of its maximum load. So with a 1000W PSU, if you are drawing 500~600W then you are probably getting the highest efficiency than with a comparable 700W (and loading it up to 600W). Check reviews of power supplies and you'd see the graphs of efficiency.

 

[ehcastro3]

thanks.

another question: lets assume that the maximum load is 80%, the amount of power my PSU will use is 800w or 600w (the one that will be charged in my electric bill)?

 

[Zenthar]

The amount of power that will be drawn from the wall can be calculated as followed: <pc wattage> ÷ <efficiency> = <Watts drawn from wall>.

Therefore if you pc is loaded at 80% (800W) and that at this load the efficiency is 84% (Corsair 1000HX), then it would be: 800W ÷ 0.84 = 952W. Loaded at 100% a 1000HX has 83% efficiency and therefore would draw ~1200W from the wall. Remember that a 120V 15A circuit (regular in North America) can safely hold ~1440W which is about the equivalent of a 1200W PSU @ 83-85% efficiency.

 

[basket687]

As amnotanoobie said, it depends on its efficiency. For example, if its efficiency at that load (600W) is 80%, then to give you 600W it will draw 750W from your wall socket, and most PSUs are most efficient around 50% of their maximum load.

 

[ehcastro3]

oh ok thanks...