Somewhere on teh intarweb "VanguardLH" typed:
> GT wrote:
>
>> Would a 650W PSU run hotter when powering a 484W computer than when
>> powering a 232W setup? Obviously case temperatures would affect
>> things, but if we could isolate that...
>>
>> Does a PSU run hotter when under more load or is its heat output
>> independent of the amount of power drawn from it?
>
> You cannot consume more power without generating more heat. More
> power means more heat.
>
> 1000 Watts = 0.948 BTU

Indeed. However, the PSU doesn't 'consume' the power, it supplies (most of)
it to other devices which consume it.

The question was really about PSU efficiency at different loads. The answer
(near enough) is that a certain amount of the output is lost as heat in the
switching process. A good PSU is rated at 80+ efficiency meaning that, if
it's putting 80W out it's using less than 100W with the difference being
lost as heat from the PSU.

Therefore, assuming that efficiency is linear (it's not but it's often
close) a 650W 80% effecient PSU would produce 121W of heat producing the
first load mentioned, 484W, and 58W of heat when delivering the power for
the 232W 'setup'.

Good link:

"Everything You Need to Know About Power Supplies"

http://www.hardwaresecrets.com/article/181/1

Cheers,
--
Shaun.

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