"Le_Forgeron" <jgr### [at] freefr> wrote in message
news:4c4bfc4b$1@news.povray.org...

> Cooler, for the PSU, is a function of the efficiency.
> For a load of 500W, a PSU 80+(basic label) would be at 50%, from 80+
> program, it means that 80%=500W, so 100% is 625W, 125W of heat.
>
> 80+ label is flat

OK, that explains it to some degree. My (dated, pre 80+ certification)
experience is with PSUs with more varied efficiency curves. I suppose 80+ is
a good thing, although I don't see the wisdom of requiring min 80% at 20%
load, but I digress.

> whatever the load ratio, so using a 800W or 1200W
> would get the same 80%, and for a load L, the same heat (125W here)

However, looking at a couple of efficiency charts like this:

http://www.corsair.com/products/hx850/hx850-efficiency-chart.gif

it seems the sweet spot is still somewhere around half load, although the
dropoff from 1/2 load to full is fairly small, and you are right, the
difference between brands/models will probably be more relevant than the
relative operating point on the curve.

Also, I'm guessing that the efficiency as well as peak deliverable go down
over time.

Considering all, I'll probably go with an 850W one.

> > Interesting (and disappointing). Is this true even if the second one is
not
> > running anything needing 3D acceleration? If so, would you recommend
messing
> > with an additional card (different, cheaper and quieter)? I've quickly
> > checked and Windows 7 seems to accomodate this...



While that's somewhat scary, my real concern is noise, not necessarily


unfortunately, OpenGL support on ATI gamer cards has left a bad impression
for me.

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