PS load

[john3850]

Suppose you have two identical pc at 100% load.
Sytem A uses a 400w ps.
Sytem B uses a 800w ps.
Will both systems use the same amount power.

Will a 80 PLUS ps save much more $ than a non 80 plus ps.

 

[TemjinGold]

Both systems will supply the same amount of power. However, the PSUs will draw a different amount of power from the wall to provide that power. All other things equal, the 800w will end up drawing more power from the wall than the 400w.

 

[theAnimal]

The amount of power drawn from the wall will depend on the PSUs efficiency rating at the given load.

A non 80Plus PSU can be quite a bit less than 80%, but so could an 80Plus PSU at very low load.

How much difference a more efficient PSU makes depends on how much you pay for electricity.

 

[john3850]

Thanks for the answers

 

[Maverick6969]

Both systems will supply the same amount of power.

No, that just doesn't make any sense. The 800w rated power supply will supply MORE power as power supplies in that category typically have a higher amps on the 12v rails. Go on new egg and compare the amps on a 450w psu versus 750w.

 

[BoomerD]

No, that just doesn't make any sense. The 800w rated power supply will supply MORE power as power supplies in that category typically have a higher amps on the 12v rails. Go on new egg and compare the amps on a 450w psu versus 750w.

The 800 watt unit will have the capacity to provide more power...but will only provide as much as the system actually demands...
The 800 watt PSU doesn't output 800 watts all the time.

If the system demands 300 watts under its heaviest load, both PSU's will output 300 watts. If one is more efficient than the other at that output, the draw from the wall will be less.
An 80% PSU on a system that uses 400 watts will pull 480 watts from the wall. (in theory anyway...the actual numbers will vary for a variety of reasons)