Hi,

I'm currently getting some parts together to build a second PC, and I have a
question regarding cooling.

A bit of background.... I also have a Dell Dimension 8300, which doesn't use
the 'normal' cooling setup for the CPU of a heatsink with fan mounted on it,
but instead has a large heatsink on the CPU, and a 120mm case fan with a
duct to draw air across and away from the CPU heatsink.
It seems to work well, at least the PC hasn't gone into meltdown yet, and is
pretty quiet.

I am using an Antec case for the second PC, which has a large 120mm case
mounted fan at the back. I am considering setting up the same config. as my
Dell to cool the CPU. I would have to make a duct to attach to the case fan
to make it draw air across the CPU heatsink, but that shouldn't be too
difficult.

I've read up on this a bit and the ducted fan arrangement seems, in theory
to be better than a heatsink mounted fan, because..
a) It is bigger and can move more air
b) Being bigger it can run a little slower and therefore be quieter
c) A heatsink fan has a deadspot in the middle, where the motor hub is,
leading to inefficient cooling.

So, what do you think?

Any recommendations re. heatsinks and places to get them? (in the UK)

Oh yes, the system in question will be running an Athlon XP2500 or XP2800,
probably not overclocked.

Regards, John

"John Fryatt" <jrf1> wrote in message
news:R2I_c.402$(E-Mail Removed)...
> Hi,
>
> I'm currently getting some parts together to build a second PC, and I have
a
> question regarding cooling.
>
> A bit of background.... I also have a Dell Dimension 8300, which doesn't
use
> the 'normal' cooling setup for the CPU of a heatsink with fan mounted on
it,
> but instead has a large heatsink on the CPU, and a 120mm case fan with a
> duct to draw air across and away from the CPU heatsink.
> It seems to work well, at least the PC hasn't gone into meltdown yet, and
is
> pretty quiet.
>
> I am using an Antec case for the second PC, which has a large 120mm case
> mounted fan at the back. I am considering setting up the same config. as
my
> Dell to cool the CPU. I would have to make a duct to attach to the case
fan
> to make it draw air across the CPU heatsink, but that shouldn't be too
> difficult.
>
> I've read up on this a bit and the ducted fan arrangement seems, in theory
> to be better than a heatsink mounted fan, because..
> a) It is bigger and can move more air
> b) Being bigger it can run a little slower and therefore be quieter
> c) A heatsink fan has a deadspot in the middle, where the motor hub is,
> leading to inefficient cooling.
>
> So, what do you think?
>
> Any recommendations re. heatsinks and places to get them? (in the UK)
>
> Oh yes, the system in question will be running an Athlon XP2500 or XP2800,
> probably not overclocked.
>
> Regards, John
>

For the time, effort, and (possibly money) involved, it might be better to
look into watercooling. -Dave

["Followup-To:" header set to uk.comp.homebuilt.]
John Fryatt was seen penning the following ode to ... whatever:
> Hi,
>
> I'm currently getting some parts together to build a second PC, and I have a
> question regarding cooling.
>
> A bit of background.... I also have a Dell Dimension 8300, which doesn't use
> the 'normal' cooling setup for the CPU of a heatsink with fan mounted on it,
> but instead has a large heatsink on the CPU, and a 120mm case fan with a
> duct to draw air across and away from the CPU heatsink.
> It seems to work well, at least the PC hasn't gone into meltdown yet, and is
> pretty quiet.

Compaq at least used to use similar arrangements in their SFF (small
form factor) machines, and they tend to be fairly quiet.

> I am using an Antec case for the second PC, which has a large 120mm case
> mounted fan at the back. I am considering setting up the same config. as my
> Dell to cool the CPU. I would have to make a duct to attach to the case fan
> to make it draw air across the CPU heatsink, but that shouldn't be too
> difficult.
>
> I've read up on this a bit and the ducted fan arrangement seems, in theory
> to be better than a heatsink mounted fan, because..
> a) It is bigger and can move more air
> b) Being bigger it can run a little slower and therefore be quieter

(a) and (b) of course are somewhat exclusive. How far away is the fan
from the CPU?

> c) A heatsink fan has a deadspot in the middle, where the motor hub is,
> leading to inefficient cooling.

Yes, but that's mostly becoming an issue if you absolutely need to
squeeze the last drop of cooling ability out of your HSF.

> So, what do you think?
>
> Any recommendations re. heatsinks and places to get them? (in the UK)

Depends on the orientation of the heatsink re the fan - you'd want
something with as much surface area as possible. Something like a
Zalman flower cooler maybe, but you'd need to make sure that air gets
drawn through the fins, not over the cooler.
--
My quiet computing page:
http://www.unixconsult.co.uk/computi...-pc-howto.html

John Fryatt wrote:
>
> Hi,
>
> I'm currently getting some parts together to build a second PC, and I have a
> question regarding cooling.
>
> A bit of background.... I also have a Dell Dimension 8300, which doesn't use
> the 'normal' cooling setup for the CPU of a heatsink with fan mounted on it,
> but instead has a large heatsink on the CPU, and a 120mm case fan with a
> duct to draw air across and away from the CPU heatsink.
> It seems to work well, at least the PC hasn't gone into meltdown yet, and is
> pretty quiet.
>
> I am using an Antec case for the second PC, which has a large 120mm case
> mounted fan at the back. I am considering setting up the same config. as my
> Dell to cool the CPU. I would have to make a duct to attach to the case fan
> to make it draw air across the CPU heatsink, but that shouldn't be too
> difficult.
>
> I've read up on this a bit and the ducted fan arrangement seems, in theory
> to be better than a heatsink mounted fan, because..
> a) It is bigger and can move more air
> b) Being bigger it can run a little slower and therefore be quieter
> c) A heatsink fan has a deadspot in the middle, where the motor hub is,
> leading to inefficient cooling.
>
> So, what do you think?

Im' using a ducted fan for a P4 Northwood build. You could use a huge
gigantic heatsink and it could possibly be passive. The problem is
attaching a large weight to the CPU and make the installation stable.
Intel specifies a weight limit on HS+fan of 450 gr. The Zalman duct
fan that I use is 500 gr with fan, so it's just about the limit. I know
that you'll be running an AMD processor, but similar considerations may
apply.

"John Fryatt" <(E-Mail Removed)> wrote:

>A bit of background.... I also have a Dell Dimension 8300, which doesn't use
>the 'normal' cooling setup for the CPU of a heatsink with fan mounted on it,
>but instead has a large heatsink on the CPU, and a 120mm case fan with a
>duct to draw air across and away from the CPU heatsink.
>It seems to work well, at least the PC hasn't gone into meltdown yet, and is
>pretty quiet.

<snip>

>I've read up on this a bit and the ducted fan arrangement seems, in theory
>to be better than a heatsink mounted fan, because..
>a) It is bigger and can move more air
>b) Being bigger it can run a little slower and therefore be quieter
>c) A heatsink fan has a deadspot in the middle, where the motor hub is,
>leading to inefficient cooling.

>So, what do you think?

Very common in machines built by larger OEMs, such as Dell, HP/Compaq
etc. Generally very effective and much quieter than the "let's stick
this bloody aircraft turbine on this cheap nasty metal block" approach
favoured by retail and after-market coolers.

>Any recommendations re. heatsinks and places to get them? (in the UK)

I believe Dell use Coolermaster heat sinks in some of their machines
coupled with a custom duct designs. AFAIK the same solutions aren't
available retail as they need to be integrated with the case to work
properly. You could probably pick suitable OEM parts from spares
stockists or eBay, although they tend to be for P4 chips as they're
dominant in the "branded" market.

>Oh yes, the system in question will be running an Athlon XP2500 or XP2800,
>probably not overclocked.

Only ever seen these solutions used on Intel chips which, as a general
rule, don't require quite as much cooling. That said, now Prescott is
with us the OEMs will almost certainly of had to re-design their
cooling solution to cope. I've not taken a recent machine apart to
see if they're still using the same fan/duct approach.

The only OEM machine I came across using an AMD chip used the more
"conventional" cooler which might imply they couldn't get sufficient
cooling using the kind of solution you're looking to use but that's
not to say it can't be done.


--
>iv< Paul >iv<

John Fryatt wrote:
> Hi,
>
> I'm currently getting some parts together to build a second PC, and I
> have a question regarding cooling.
<...>
> I am using an Antec case for the second PC, which has a large 120mm
> case mounted fan at the back. I am considering setting up the same
> config. as my Dell to cool the CPU. I would have to make a duct to
> attach to the case fan to make it draw air across the CPU heatsink,
> but that shouldn't be too difficult.
>
> I've read up on this a bit and the ducted fan arrangement seems, in
> theory to be better than a heatsink mounted fan, because..
> a) It is bigger and can move more air
> b) Being bigger it can run a little slower and therefore be quieter
> c) A heatsink fan has a deadspot in the middle, where the motor hub
> is, leading to inefficient cooling.
>
> So, what do you think?

I am a duct enthusiast (I couldn't say fan, could I?) and I wrote up an
article on my website in the 'Miscellanea' section about 'Recent
xp1800+ build' as it was at the time. [It's now a xp3200+ !]

>
> Oh yes, the system in question will be running an Athlon XP2500 or
> XP2800, probably not overclocked.

Get the mobile XP-M2500+ which runs cooler and is unlocked.

HTH
--
Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

"Paul Hopwood" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> "John Fryatt" <(E-Mail Removed)> wrote:
> >A bit of background.... I also have a Dell Dimension 8300, which doesn't
> >use the 'normal' cooling setup for the CPU of a heatsink with fan mounted
> >on it, but instead has a large heatsink on the CPU, and a 120mm case fan
> >with a duct to draw air across and away from the CPU heatsink.
[snip]
> Only ever seen these solutions used on Intel chips which, as a general
> rule, don't require quite as much cooling.

Now come on Paul, you know better than that. The difference between AMD and
Intel's mainstream chips (in processing power vs dissipated power) became
pretty small when the P4 first appeared, and has certainly been small enough
to be ignored for a couple of years.

Alex

> Only ever seen these solutions used on Intel chips which, as a general
> rule, don't require quite as much cooling. That said, now Prescott is
> with us the OEMs will almost certainly of had to re-design their
> cooling solution to cope. I've not taken a recent machine apart to
> see if they're still using the same fan/duct approach.

My Dell machine, which is the ducted cooling machine referred to earlier,
uses a Prescott.

Hi Graham,

Took a look at your Web page. Excellent, and it reinforced my plan to go the
duct route.
I am not obsessive about it but the idea of lots of roaring fans is not a
good thing, for me.

I saw a PC for sale on eBay recently which purported to have 12 fans! The
thing must sound like a Bell Jetranger when it starts up! :-(

Regards, John


"Graham W" <(E-Mail Removed)> wrote in message
news:413b8eb8$0$75650$(E-Mail Removed)...
> John Fryatt wrote:
> > Hi,
> >
> > I'm currently getting some parts together to build a second PC, and I
> > have a question regarding cooling.
> <...>
> > I am using an Antec case for the second PC, which has a large 120mm
> > case mounted fan at the back. I am considering setting up the same
> > config. as my Dell to cool the CPU. I would have to make a duct to
> > attach to the case fan to make it draw air across the CPU heatsink,
> > but that shouldn't be too difficult.
> >
> > I've read up on this a bit and the ducted fan arrangement seems, in
> > theory to be better than a heatsink mounted fan, because..
> > a) It is bigger and can move more air
> > b) Being bigger it can run a little slower and therefore be quieter
> > c) A heatsink fan has a deadspot in the middle, where the motor hub
> > is, leading to inefficient cooling.
> >
> > So, what do you think?
>
> I am a duct enthusiast (I couldn't say fan, could I?) and I wrote up an
> article on my website in the 'Miscellanea' section about 'Recent
> xp1800+ build' as it was at the time. [It's now a xp3200+ !]
>
> >
> > Oh yes, the system in question will be running an Athlon XP2500 or
> > XP2800, probably not overclocked.
>
> Get the mobile XP-M2500+ which runs cooler and is unlocked.
>
> HTH
> --
> Graham W http://www.gcw.org.uk/ PGM-FI page updated, Graphics Tutorial
> WIMBORNE http://www.wessex-astro-society.freeserve.co.uk/ Wessex
> Dorset UK Astro Society's Web pages, Info, Meeting Dates, Sites & Maps
> Change 'news' to 'sewn' in my Reply address to avoid my spam filter.

Thanks all for the advice. I kind of expected to get replies saying "don't
be stupid, use the fan/heatsink", so I am quite gratified to see some
positive remarks.
I think I'll give the duct and passive heatsink a try. I like my new Dell
for its relative quietness, and I'll try to get similar levels from the
second machine. Unfortunatley I've ended up with a Radeon graphics card*
which does have a small fan. Can't win 'em all I suppose. ;-)
Maybe I'll try taking off the fan and attaching a larger heatsink, but
that's one for the future, once I get the box up and working.

John

* - not an issue with the Dell as it isn't a gaming box so I'm using a
Matrox card which doesn't need a fan.


"John Fryatt" <(E-Mail Removed)> wrote in message
news:R2I_c.402$(E-Mail Removed)...
> Hi,
>
> I'm currently getting some parts together to build a second PC, and I have
a
> question regarding cooling.
>
> A bit of background.... I also have a Dell Dimension 8300, which doesn't
use
> the 'normal' cooling setup for the CPU of a heatsink with fan mounted on
it,
> but instead has a large heatsink on the CPU, and a 120mm case fan with a
> duct to draw air across and away from the CPU heatsink.
> It seems to work well, at least the PC hasn't gone into meltdown yet, and
is
> pretty quiet.
>
> I am using an Antec case for the second PC, which has a large 120mm case
> mounted fan at the back. I am considering setting up the same config. as
my
> Dell to cool the CPU. I would have to make a duct to attach to the case
fan
> to make it draw air across the CPU heatsink, but that shouldn't be too
> difficult.
>
> I've read up on this a bit and the ducted fan arrangement seems, in theory
> to be better than a heatsink mounted fan, because..
> a) It is bigger and can move more air
> b) Being bigger it can run a little slower and therefore be quieter
> c) A heatsink fan has a deadspot in the middle, where the motor hub is,
> leading to inefficient cooling.
>
> So, what do you think?