~misfit~ wrote:

> 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.

True, but since efficiency is never 100% then the more power consumed by
the target devices (mobo, memory, cards, drives, etc.) means the more
power also consumed by the PSU. For a 600W PSU, if efficiency were 70%
(a measure in difference between input and output power at some load), a
load of 300W means the PSU is consuming 75W (300/.8 - 300, or 375W input
power minus the 300W load). For a 400W load, the PSU eats 100W (
400W/.8 - 400W, or 500W input power minus the 400W load). As the PSU
consumes more power under a higher load, the more heat is produced by
the PSU itself. Of course, assuming 80% efficiency is being generous
since, as you said, that's typical of "good" power supplies.

So back to the OP's question of will a PSU run hotter with a 484W load
than with a 232W load, and whether efficiency were 70% or 80% for the
PSU, my answer still applies. More power consumed means more heat. No
matter what PSU the OP uses and irrelevant of the PSU's maximum capacity
(i.e., max load), you cannot *consume* more power without generating
more heat because. Efficiency is never 100% for the PSU.