On Tue, 30 Jan 2007 23:51:29 -0000, "Kroma"
<NOSPAMPLEASE@btinternet.com> wrote:
>Hi,
>
>I've just had to replace my PSU after the last one started smoking. My new
>PSU only has a single fan (the last had 2) and as a result I've noticed that
>my PC temperatures are up.
OK, but are they now TOO high?
If not too high, you are done.
Otherwise, it is a bad idea on a semi-modern system to rely
on the PSU for much of the airflow, that's what the rear
chassis fan's purpose is.
>
>My motherboard goes up to 41C and the CPU to around 61C when in use. I have
>a Pentium4 2.66
What does "In use" mean? The relevant temp is at full load,
running Prime95's Torture Test for 30 minutes THEN taking a
reading, for example. You'd then compare this to the prior
temp under the old PSU configuration... which you may not be
able to do, but the key is how hot it gets at peak, now.
>
>So, I've decided that a case fan is the way to go.
You didn't have a case fan yet?
If not, yes you should('ve) had one already.
>
>I've chosen a fan:
>
>http://tinyurl.com/2fle8k which is the correct size and has the correct
>connections.
It also has fairly low RPM/airflow, which is good for
limiting noise production, but also means lower airflow. On
a modern system I'd use two of those on the rear of the
case, or use a different case. Your needs may differ.
Those transparent fans are also more rigid than their black
counterparts and will transmit more vibration to the case =
louder when all else is equal. We can't know exactly how
well balanced they are, which is also quite important, but
at least with their relatively low RPM the resultant
vibration shouldn't be very bad if they are of reasonable
quality.
>
>However, having looked at the rear of my ATX case I'm a little unsure - I
>was expecting lots of holes or a removable section - but I have some grilles
>(marked 'Dual fan system'). The lower grill is for a 70mm fan and the upper
>for an 80mm (the one I've chosen, right)?
>
>The case looks like this from the outside:
>
>http://tinyurl.com/3c35vq
First, it looks like the replacement PSU is bad, I mean
junk. I could be wrong but felt it may be important to
mention now. What make, model and 12V current does it
support, and what are all the major parts in the system?
As for the rear vents, they're almost worthless. The case
isn't usable like that, I would either replace the whole
case or strip it down (take out all parts) and cut out fan
holes for two of the above linked fans or as mentioned, two
equivalent black (plastic) ones.
Since the rear has such poor exhaust area, it wouldn't
surprise me if the front isn't much better, but I suspect
I'll see that with the below link.
>
>and like this from the inside:
>
>http://tinyurl.com/2qheg5
>
I was hoping for an inside view of the front wall of the
case, but a comment about that rear- it "looks" like it is
for 80mm fans, not big eough for 92mm unless you ignored the
original holes but that would be a more difficult way to cut
out that area so I still suggest 2 x 80mm fans, and of
course you'll need at least 4 screws, but personally I'd
drill out the holes to use 4 screws per each fan, 8 total.
By having all 4 screws you will possibly reduce vibrations
between case and fan frame, get a better seal between fan
frame and case wall (especially if cutting out the holes
makes the metal somewhat less planar afterwards), and
strengthen the area some with two larger holes in it.
It is theoretically possible to take some pliers and bend
those slots up a LOT, increasing the exhaust area exposed
behind the fan, but the resulting airflow will still be a
lot lower than cutting them out entirely, and it might be
noisier to keep them too.
>Note that the grilles have a kind of metal canopy over them - I presume to
>prevent dust ingress?
Perhaps that was the idea, but most cases don't have this
canopy design. Since you didn't have fans installed it was
actually better (until now, since you need fans for a modern
system) that the holes be more restrictive to airflow, as
otherwise it would have created a short loop that interfered
with more passive intake through the front of the case.
Hence what I'd hoped for previously, a picture of the inside
front of the case as the rear fan effectiveness at
exhausting air depends on how well it can draw air in - and
in the front is best as the air then passes over the most
parts, may be the only method of cooling the front drive
rack and often the motherboard chipset.
>
>So - how would I fit the fan? Do I simply hold it against the inside of the
>case and screw from the outside?
Yes after you cut out the hole or use the pliers to increase
the slit open area.
> The picture of the fan shows a 'layered'
>surround of the fan - are the screws really long and they simply screw
>through the case, through the first layer and then the second?
You only need to screw through the first "layer" of the fan.
>
>I can also only locate 2 holes (and that's all they are - holes) for screws
>I presume. Will that suffice?
Well it's a lot better than only one... but they should've
used 4. You can try it with two, but I'd go ahead and drill
out the other 2 holes per fan, while the parts were out,
after cutting out the hole.
>
>Or am I wrong and I need to remove something (there doesn't seem to be
>anything to remove though).
>
>I'm sure it's a very simple job but I don't want to make a silly mistake!
It should've been simple to install a fan but that case
isn't designed very well. You could just put a fan in as
you suggested and see how it does, but it would do a lot
better with the methods I've described above.
Case fan installation 
Linear Mode
