Question about Power Supplies and Heat

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Thunder9

If I get a larger power supply... say 450w instead of 350w... does
that itself create significantly more heat? Or is the heat generated
solely dependent on the amount of power required/consumed by the
components?

Thanks,
Thunder9
 
If I get a larger power supply... say 450w instead of 350w... does
that itself create significantly more heat? Or is the heat generated
solely dependent on the amount of power required/consumed by the
components?

Thanks,
Thunder9
Click to expand...

On the same box I found a 400W PS put out way more heat than a 200W PS
that I have in it now. It has a Barton 2500+ @ 3200+.
 
Heat produced by supply is a function of design. Some
switching power supplies can produce more heat when not fully
loaded and produce less heat when fully loaded. The answer is
unique to each supply's design and is answered by
specifications provided by that supply manufacturer. Some
supplies are simply more efficient than others.
 
If I get a larger power supply... say 450w instead of 350w... does
that itself create significantly more heat? Or is the heat generated
solely dependent on the amount of power required/consumed by the
components?

Thanks,
Thunder9
Click to expand...

The heat generated is dependent partly on the amount of power drawn by
the components, AND by the efficiency of the power supply unit.

While it is entirely possible to get a 450W power supply that's more
inefficient than a lower power one, most of the time, a higher rated
supply will be more efficient than a lower rated one. This means that
all things being equal, a 450W supply should run cooler than a 350W.
 
Thunder9 said:
If I get a larger power supply... say 450w instead of 350w... does
that itself create significantly more heat?
No.

Or is the heat generated
solely dependent on the amount of power required/consumed by the
components?
Click to expand...

Yes.
 
Yes.
Click to expand...

Ok I did some research and, as other posters also indicated, this is
incorrect. The heat generated /* by the power supply */ is due to its
efficiency. Thus if the PSU was 100% efficient at converting power
from ac to dc (which none are) then the psu would produce no heat. If
the power supply was 50% efficient, then it would take, for example,
300 watts of power to produce 150 watts of usable energy, and that
extra 150 watts would be converted into heat at the PSU.

For an excellent artical on this, check out...
http://www.silentpcreview.com/modul...ns&file=index&req=viewarticle&artid=28&page=1

Regards,
Thunder9
 
Efficiency is not constant. The efficiency number changes
with load. Typically, it does not change much. But it does
change.
 
Thunder9 said:
Ok I did some research and, as other posters also indicated,
this is incorrect. The heat generated /* by the power supply
*/ is due to its efficiency. Thus if the PSU was 100% efficient
at converting power from ac to dc (which none are) then the
psu would produce no heat. If the power supply was 50%
efficient, then it would take, for example, 300 watts of power
to produce 150 watts of usable energy, and that
extra 150 watts would be converted into heat at the PSU.

For an excellent artical on this, check out...
Click to expand...
http://www.silentpcreview.com/modul...ns&file=index&req=viewarticle&artid=28&page=1


Be aware that voltage regulation reduces the efficiency
of a power supply while increasing its stability and cleanliness
of output. Judging a power supply soley by its efficiency
would be a mistake (not that you've done that).


*TimDaniels*
 
Thunder9 said:
Ok I did some research and, as other posters also indicated, this is
incorrect. The heat generated /* by the power supply */ is due to its
efficiency. Thus if the PSU was 100% efficient at converting power
from ac to dc (which none are) then the psu would produce no heat. If
the power supply was 50% efficient, then it would take, for example,
300 watts of power to produce 150 watts of usable energy, and that
extra 150 watts would be converted into heat at the PSU.
Click to expand...

Your point being? A 250 watt PSU outputting 200 watts at 70% efficiency
would have an input of 200/.7 watts or 285.7 watts. The extra 85.7 watts
would be dissipated mainly as heat. A 450 watt PSU outputting the same
200 watts at 70% efficiency would have the same input of 285.7 watts,
with the same 85.7 watts again being dissipated mainly as heat.

If anything, the 450 watt PSU would have it's output rectifiers and
magnetics running at a lower percentage of their full rating, thereby
running cooler. [PSU efficiency *is* affected greatly by how much power
it's components dissipate, after all. That is the #1 factor determining
PSU efficiency.]

Nothing in the article at the URL you gave indicates otherwise.
 
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