So you see no problem with a PSU that has fans blowing air
out, but no way for much air to go into the PSU? Personally,
I would think competing fans might actually make the PSU
hotter.
What I meant was that there aren't any PSU made that blow
into the case instead of out, AFAIK, but even if there were
it would not make the PSU hotter it would tend to make it a
little cooler running at the expense of the rest of the
system getting hotter.
Instead what seemed more likely was that this is one of many
PSU that have the bottom fan but also have some slits on the
rear such that some of the intake air is blown back into
case... this is usually not a big problem as it is a small
percentage compared to what is exhausted out the back, but
if the case intake is very poor or the PSU exhaust area is
mostly obstructed then the % would start climbing. Overall
I still suspect a combination of poor psu and poor case
intake.
True, at least in the since that the hot air from the PSU
had no place to go , but onto the CPU heat sink, with the
side on. With the side off, there would be a path that allows
it to flow, and even hot air can carry away heat, if it is
moving air.
Yes, taking the case side panel off should improve the
situation but it should already be fairly obvious whether
the case has ample front intake (and perhaps a side fan or
grate) or not. I suppose we should determine for certain if
the PSU fan were really reversed and blowing the wrong
direction, but "think the fan is blowing into the case"
seems fairly ambiguous to me, it should be pretty obvious by
looking at the fan and the blade slope/curvature, which way
it's blowing when spinning even if not powered so the fan
isn't spinning at the moment.
How about: it's a function of the air flow through the
PSU case?
That too, but given a fast enough fan the PSU still
shouldn't be that hot... just too noisey. Then again "hot"
is a bit of a relative perception without a temp reading
number. Even so, it takes a fairly poor setup for the PSU
casing to feel more than barely warm except when it's
completely off in S5 state the 5VSB current generation
without a fan running can tend to make some a little warmer.
If you have a box with competing fans;
where both are trying to blow air in or trying to blow
the air out, you aren't going to have much air flow.
You'd certainly have less, but unless the rest of the case
were very poor and no passive intake (or exhaust in this
case) it should still be providing enough airflow that the
PSU doesn't get terribly hot, unless it's quite poor,
inefficient, or the fans aren't running fast enough.
Note that most OEMs do use this "competing fan" arrangement
on the majority of their PC systems, with both the PSU fan
and the rear case/passive-CPU fan both blowing outward and
they manage to do it even without much noise.
The
best practice, with multiple fans, is to have intake fans in
one corner of the box and the exhaust fans in the opposite
corner, so the air flows through the whole box.
Absolutely, with one exception that the gain by doing this
can be offset by the increased noise emission having a fan
in the front where the sound can escape and be more easily
perceived by the user. Even then, when that intake fan is
forced through the HDD rack it does a much better job of
keeping multiple drives cool.
Since
hot air rises, it is natural to have the intake at or near the
bottom and the exhaust at or near the top.
Hot air rising isn't much of a concern when it's being
actively moved by a couple fans. More significant is what
you already wrote, that the intake (whether it be a fan or
just passive) and exhaust are at opposite *corners* of the
system as much as reasonably possible.
