PSU question

Cavallino · 12 Oct 2009 at 23:06

Assume I have a 650w and 850w PSU made by the same manufacturer. Assuming a mid range load of around 200 watts or so, which would use more heat/draw more current?

Or would they both be equal?

Sasahara · 12 Oct 2009 at 23:20

I assume by use more heat you mean produce more heat, as they won't use heat.

Different PSUs, even in the same series could use the same or different amounts of current, there's no definative answer to this question.

What you want to know is the level of efficiency at 200w load, to get a correct answer you have to state specific PSUs. (And that would only be a guide as even 2 identical PSUs could have some small level of variable results)

Cavallino · 12 Oct 2009 at 23:34

Sasahara said:
I assume by use more heat you mean produce more heat, as they won't use heat.

Different PSUs, even in the same series could use the same or different amounts of current, there's no definative answer to this question.

What you want to know is the level of efficiency at 200w load, to get a correct answer you have to state specific PSUs. (And that would only be a guide as even 2 identical PSUs could have some small level of variable results)

Yes sorry I meant to say "dissipate heat".

So you are saying that a 850 watt could potentially draw more current than a 650 depending on efficiencies?
Ok assuming both have equal efficiency ratings, would this mean that both would draw same amount of current for the same wattage? (despite one being rated higher than the other?)

Kennysevenfold · 13 Oct 2009 at 08:53

Use the 650.

Sasahara · 13 Oct 2009 at 09:00

Cavallino said:
Yes sorry I meant to say "dissipate heat".

So you are saying that a 850 watt could potentially draw more current than a 650 depending on efficiencies?
Ok assuming both have equal efficiency ratings, would this mean that both would draw same amount of current for the same wattage? (despite one being rated higher than the other?)

If both had the same efficiency at 200w output they would use the same amount of current.

But the sweet sport of a PSU tends to be above 25% load, so running an 850w PSU at 200w draw probably won't be as efficient as a 650w at 200w.

But again all PSUs will be different so that's not definative.

The 650w would be the one to pick for most people.