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COPPER CPU SHIMS: The Definitive Answer !!

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August 20, 2004 10:44:09 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

Ok, my gut feeling was that installing a copper shim was a mod that could
provide measurable benefits. My reasoning was as follows: Presently my
Maze3 waterblock is only slightly warm at the edges of the block, indicating
a large thermal gradient between the center water channel and the outer
water channel, and thus plenty of cooling power still available if some heat
could be diverted to the outer portion of the waterblock, instead of simply
the 1cm x 1.5cm cpu core area (non-heat-spreader cpu).

Now, given that the cpu thermistor is on the other side of the substrate on
the botom of the cpu and is registering quite a high temp, and that the cpu
electrical traces (which permeate the substrate) most definitely are
significant thermal conductors, it seems very reasonable to me to conclude
that the opportunity is there to lower temps by this multiplication of the
surface area touched by the waterblock by probably 7x or 8x.

So. On my AthlonXP 1700+ running at 10.5 x 230fsb = 2.4ghz @ 1.9v cpu, I
installed a copper shim from www.1coolpc.com (I bought the XP shim, but it
required a lot of Dremel work to get it to fit -- I suspect this is
actually a Barton shim; but anyway). I was very careful to check that the
shim did not sit higher than the cpu core, to file all edges smooth, and to
check that the shim sat completely flat on the cpu substrate. In addition,
and this is an important touch, I smeared both sides of the shim with
ArticSilver5, a thin coat. Don't get careless and blow off this step as you
will compromise much of the effectiveness of the mod.

The results are extremely satisfying!! Immediately after installation
Prime95 has stabilized at 54C, probably 10C lower than previous, and after
curing will certainly drop even farther. Now, I hear the skeptics scoffing,
and realize that it's likely the thermal characteristics of the copper shim
are not the only factor for the dramatic improvement.

I suspect that other factor consists of the large-surface-area copper shim
forcing the (large and heavy) waterblock to lie completely flat on the cpu
core. Although I've always used a fiber washer, clearly it was not
preventing a slight rocking of the heatsink from one side of the core to the
other, which could be caused by unequal spring pressure or simply gravity.

Both of these factors make the copper shim a must-have addition to a
high-performance Barton or other non-heatspreader-type cpu installation,
IMHO. There is no doubt in my mind that people running very heavy heatsinks
like the SP-97 or big waterblocks will see an immediate temperature
reduction from careful installation of a copper shim.

rms
Anonymous
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a b K Overclocking
August 20, 2004 5:44:56 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

In comp.sys.ibm.pc.hardware.chips rms <rsquires@flashremove.net> wrote:
> as follows: Presently my Maze3 waterblock is only slightly
> warm at the edges of the block, indicating a large thermal
> gradient between the center water channel and the outer water

True if the center water edges are much warmer than the
outside edges. Did the outside edges warm up with the shim?

> The results are extremely satisfying!! Immediately after
> installation Prime95 has stabilized at 54C, probably 10C

No denying data. I wouldn't call prime95 very severe,
but I'm biased.

> I suspect that other factor consists of the
> large-surface-area copper shim forcing the (large and
> heavy) waterblock to lie completely flat on the cpu core.
> Although I've always used a fiber washer, clearly it was
> not preventing a slight rocking of the heatsink from one
> side of the core to the other, which could be caused by
> unequal spring pressure or simply gravity.

Rocking or edge contact with a die-back is extremely
detremental to heat-transfer, even with high-k heat compound.
I always check for this and correct grease spreading by very
slightly rotating the HS after installation. I'm looking
for a very heavy, smooth drag. Any sign of scraping (other
than from the clamp) means trouble.

I suspect this was the biggest effect, but heat spreaders
can be useful (seen by a reduction in center/edge gradients
on the HS)

-- Robert author `cpuburn` http://pages.sbcglobal.net/redelm
August 20, 2004 9:15:45 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

> I suspect this was the biggest effect, but heat spreaders
> can be useful (seen by a reduction in center/edge gradients
> on the HS)

Heatsinks do perform differently when used with large-area vs.
small-area heatsources, as shown by any of the
http://www.frostytech.com/index.cfm reviews, and it seems evident to me that
waterblocks will always do better with a large-area heatsource.

> -- Robert author `cpuburn` http://pages.sbcglobal.net/redelm

cpuburn does indeed raise cpu temps farther than prime95, in my case
about 4C higher. The reason I've always used Prime95 is the error-checking
that I know it does, which gives me a clear indication that I have a
problem. It's not clear to me that cpuburn has any error-checking?

rms
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Anonymous
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August 20, 2004 10:15:14 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

If your 'old' temps were 64C with water cooling you obviously has something
seriously wrong with your installation. Even 54C is not great given that I'm
getting 44C with air cooling at 2640MHz / 1.93V (Abit NF7-S / XP-M 2500+ /
SP-97, no shim).
Shims make no significant difference to cooling performance, any properly
installed heatsink will already be sitting flat on the CPU anyway.

--
*****Replace 'NOSPAM' with 'btinternet' in the reply address*****
"rms" <rsquires@flashREMOVE.net> wrote in message
news:Z4hVc.300$l%2.0@newssvr15.news.prodigy.com...
> Ok, my gut feeling was that installing a copper shim was a mod that could
> provide measurable benefits. My reasoning was as follows: Presently my
> Maze3 waterblock is only slightly warm at the edges of the block,
> indicating a large thermal gradient between the center water channel and
> the outer water channel, and thus plenty of cooling power still available
> if some heat could be diverted to the outer portion of the waterblock,
> instead of simply the 1cm x 1.5cm cpu core area (non-heat-spreader cpu).
>
> Now, given that the cpu thermistor is on the other side of the substrate
> on the botom of the cpu and is registering quite a high temp, and that the
> cpu electrical traces (which permeate the substrate) most definitely are
> significant thermal conductors, it seems very reasonable to me to conclude
> that the opportunity is there to lower temps by this multiplication of the
> surface area touched by the waterblock by probably 7x or 8x.
>
> So. On my AthlonXP 1700+ running at 10.5 x 230fsb = 2.4ghz @ 1.9v cpu, I
> installed a copper shim from www.1coolpc.com (I bought the XP shim, but it
> required a lot of Dremel work to get it to fit -- I suspect this is
> actually a Barton shim; but anyway). I was very careful to check that the
> shim did not sit higher than the cpu core, to file all edges smooth, and
> to check that the shim sat completely flat on the cpu substrate. In
> addition, and this is an important touch, I smeared both sides of the shim
> with ArticSilver5, a thin coat. Don't get careless and blow off this step
> as you will compromise much of the effectiveness of the mod.
>
> The results are extremely satisfying!! Immediately after installation
> Prime95 has stabilized at 54C, probably 10C lower than previous, and after
> curing will certainly drop even farther. Now, I hear the skeptics
> scoffing, and realize that it's likely the thermal characteristics of the
> copper shim are not the only factor for the dramatic improvement.
>
> I suspect that other factor consists of the large-surface-area copper shim
> forcing the (large and heavy) waterblock to lie completely flat on the cpu
> core. Although I've always used a fiber washer, clearly it was not
> preventing a slight rocking of the heatsink from one side of the core to
> the other, which could be caused by unequal spring pressure or simply
> gravity.
>
> Both of these factors make the copper shim a must-have addition to a
> high-performance Barton or other non-heatspreader-type cpu installation,
> IMHO. There is no doubt in my mind that people running very heavy
> heatsinks like the SP-97 or big waterblocks will see an immediate
> temperature reduction from careful installation of a copper shim.
>
> rms
>
August 20, 2004 10:15:15 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

> If your 'old' temps were 64C with water cooling you obviously has
> something seriously wrong with your installation. Even 54C is not great
> given that I'm getting 44C with air cooling at 2640MHz / 1.93V (Abit NF7-S
> / XP-M 2500+ / SP-97, no shim).
> Shims make no significant difference to cooling performance, any properly
> installed heatsink will already be sitting flat on the CPU anyway.

A typical lousy off-hand response. I'm running a 2yr-old xp, not a
mobile barton. And I suspect that *most* installations do not conform to
your definition of a 'properly installed heatsink'.

rms
Anonymous
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a b K Overclocking
August 20, 2004 10:48:07 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

"rms" <rsquires@flashREMOVE.net> wrote
> > If your 'old' temps were 64C with water cooling you obviously has
> > something seriously wrong with your installation. Even 54C is not great
> > given that I'm getting 44C with air cooling at 2640MHz / 1.93V (Abit
NF7-S
> > / XP-M 2500+ / SP-97, no shim).
> > Shims make no significant difference to cooling performance, any
properly
> > installed heatsink will already be sitting flat on the CPU anyway.
>
> A typical lousy off-hand response. I'm running a 2yr-old xp, not a
> mobile barton. And I suspect that *most* installations do not conform to
> your definition of a 'properly installed heatsink'.

60C is where instabilities can begin to appear. Water cooling should do much
better.

--
Ed Light

Smiley :-/
MS Smiley :-\

Send spam to the FTC at
uce@ftc.gov
Thanks, robots.
Anonymous
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a b K Overclocking
August 20, 2004 11:10:21 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

rms wrote:

>>If your 'old' temps were 64C with water cooling you obviously has
>>something seriously wrong with your installation. Even 54C is not great
>>given that I'm getting 44C with air cooling at 2640MHz / 1.93V (Abit NF7-S
>>/ XP-M 2500+ / SP-97, no shim).
>>Shims make no significant difference to cooling performance, any properly
>>installed heatsink will already be sitting flat on the CPU anyway.
>
>
> A typical lousy off-hand response. I'm running a 2yr-old xp, not a
> mobile barton. And I suspect that *most* installations do not conform to
> your definition of a 'properly installed heatsink'.
>
> rms
>
>

I'm pretty sure that what he means by 'properly installed' is the heatsink
sitting flat on the core and he would be correct.
Anonymous
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a b K Overclocking
August 20, 2004 11:16:06 PM

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--
*****Replace 'NAPALM'S with 'bitternut's in the reply address*****
"rms" <rsquires@flashREMOVE.net> wrote in message
news:o vqVc.1704$BR.697@newssvr16.news.prodigy.com...
>> If your 'old' temps were 64C with water cooling you obviously has
>> something seriously wrong with your installation. Even 54C is not great
>> given that I'm getting 44C with air cooling at 2640MHz / 1.93V (Abit
>> NF7-S / XP-M 2500+ / SP-97, no shim).
>> Shims make no significant difference to cooling performance, any properly
>> installed heatsink will already be sitting flat on the CPU anyway.
>
> A typical lousy off-hand response. I'm running a 2yr-old xp, not a
> mobile barton. And I suspect that *most* installations do not conform to
> your definition of a 'properly installed heatsink'.
>
> rms
>
Suspect what you want.... Maybe most of the ones you build are not properly
installed, in fact I'm pretty certain of it.
Certainly every system that I've ever put together achieves my definition of
'properly installed' (and I've built hundreds) and even the ones with stock
air cooling achieve temps similar to your water cooled ones.

I've also tried shim's and I know for certain they make no difference that
can be recorded .... unless you are comparing to a system built by an ape.
Anonymous
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a b K Overclocking
August 20, 2004 11:21:35 PM

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"rms" <rsquires@flashREMOVE.net> wrote in message
news:5lqVc.1703$YM.409@newssvr16.news.prodigy.com...
>> I suspect this was the biggest effect, but heat spreaders
>> can be useful (seen by a reduction in center/edge gradients
>> on the HS)
>
> Heatsinks do perform differently when used with large-area vs.
> small-area heatsources, as shown by any of the
> http://www.frostytech.com/index.cfm reviews, and it seems evident to me
> that waterblocks will always do better with a large-area heatsource.
>
>
> rms
A shim does not increase the 'heat source' area... The only part of a chip
that produces heat is the core and without increasing the size of the
silicon you cant make the core area larger.
The CPU substrate produces no heat and is also a VERY poor conductor of heat
from the core, therefore the heat path from the core, thru' the substrate,
thru' the shim, thru the air gap (because the shim has a small clearance
between substrate and heatsink) and into the heatsink is virtually non
existant.
August 21, 2004 12:09:48 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

> The CPU substrate produces no heat and is also a VERY poor conductor of
> heat from the core, therefore the heat path from the core, thru' the
> substrate, thru' the shim, thru the air gap (because the shim has a small
> clearance between substrate and heatsink) and into the heatsink is
> virtually non existant.

Guess you didn't read or didn't understand what I wrote in the original
post, in which case there is no reason to respond further to you.

rms
Anonymous
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a b K Overclocking
August 21, 2004 12:30:11 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

rms wrote:
[...]
> The results are extremely satisfying!! Immediately after installation
> Prime95 has stabilized at 54C, probably 10C lower than previous, and
> after curing will certainly drop even farther. Now, I hear the
> skeptics scoffing, and realize that it's likely the thermal
> characteristics of the copper shim are not the only factor for the
> dramatic improvement.

I know this is a bit more work, but the results would be significantly more
meaningful if you remounted the block several times, both with and without
the shim. I've noticed up to a ~5 deg C variation (as in +/- 3 deg C or so)
of diode temps when remounting a TT Silent Boost, so there's a good chance
the real change is reasonably different from what you got above. Finally, it
would be great if you could find a plastic (not mica, which is also a good
thermal conductor) shim and repeat. Most plastic shims are good thermal
insulators.

> I suspect that other factor consists of the large-surface-area copper
> shim forcing the (large and heavy) waterblock to lie completely flat
> on the cpu core. Although I've always used a fiber washer, clearly
> it was not preventing a slight rocking of the heatsink from one side
> of the core to the other, which could be caused by unequal spring
> pressure or simply gravity.

This would show up in repeated tests. Another thing that could be causing it
is that you didn't crank it as tight when you first mounted it (or it
loosened over time)without the shim. Again, repeated measurements would
demonstrate this.

One thing you might want to try, if you know people with the equipment
(local university or search and rescue, possibly?), is to take thermal
images of the block from above, with and without the shim. If your
temperature is accurate (and assuming water temp ~20 deg C), then a drop of
10 deg C implies that you have about 20% of the heat flowing through the
shim, which should definately show up on a thermal image.

[...]
--
Michael Brown
www.emboss.co.nz : OOS/RSI software and more :) 
Add michael@ to emboss.co.nz - My inbox is always open
August 21, 2004 12:30:12 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

> If your
> temperature is accurate (and assuming water temp ~20 deg C), then a drop
> of
> 10 deg C implies that you have about 20% of the heat flowing through the
> shim

I did not imply this. If the difference is simply a result of a skewed
heatsink, the shim would show no temperature increase. I'm saying that a
copper shim gives dual benefits: a flatter more stable platform for the
heatsink, and additional surface area for heat dissipation. Where the
balance lies between those two I can't say.

rms
August 21, 2004 12:30:13 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

A slightly easier way to test would be to put a thermistor on the outer edge
of the heatsinks contact surface both with and without the shim.
--


"I don't cheat to survive. I cheat to LIVE!!"
- Alceryes

"rms" <rsquires@flashREMOVE.net> wrote in message
news:RejVc.301$7g3.210@newssvr15.news.prodigy.com...
>> If your
>> temperature is accurate (and assuming water temp ~20 deg C), then a drop
>> of
>> 10 deg C implies that you have about 20% of the heat flowing through the
>> shim
>
> I did not imply this. If the difference is simply a result of a skewed
> heatsink, the shim would show no temperature increase. I'm saying that a
> copper shim gives dual benefits: a flatter more stable platform for the
> heatsink, and additional surface area for heat dissipation. Where the
> balance lies between those two I can't say.
>
> rms
>
Anonymous
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a b K Overclocking
August 21, 2004 12:38:49 AM

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In comp.sys.ibm.pc.hardware.chips rms <rsquires@flashremove.net> wrote:
> cpuburn does indeed raise cpu temps farther than prime95, in
> my case about 4C higher. The reason I've always used Prime95
> is the error-checking that I know it does, which gives me a
> clear indication that I have a problem. It's not clear to me
> that cpuburn has any error-checking?

Yes, burn* do error checking on the calcs they do. I don't
push this feature because I'm not exhaustively checking for
all possible CPU errors (fully exercising the instruction set).

I've had very few reports of error reports except on burnBX
and burnMMX which usually abend from memory/bus errors.

-- Robert
Anonymous
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August 21, 2004 1:43:28 AM

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"rms" <rsquires@flashREMOVE.net> wrote in message
news:gUsVc.5673$FV3.3558@newssvr17.news.prodigy.com...
>> The CPU substrate produces no heat and is also a VERY poor conductor of
>> heat from the core, therefore the heat path from the core, thru' the
>> substrate, thru' the shim, thru the air gap (because the shim has a small
>> clearance between substrate and heatsink) and into the heatsink is
>> virtually non existant.
>
> Guess you didn't read or didn't understand what I wrote in the original
> post, in which case there is no reason to respond further to you.

read it, understood it, disagreed with it.
Anonymous
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August 21, 2004 1:58:02 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

> Now, given that the cpu thermistor is on the other side of the substrate
> on the botom of the cpu and is registering quite a high temp, and that the
> cpu electrical traces (which permeate the substrate) most definitely are
> significant thermal conductors, it seems very reasonable to me to conclude
> that the opportunity is there to lower temps by this multiplication of the
> surface area touched by the waterblock by probably 7x or 8x.
>

Just because the substrate gets hot on the back does not mean it's a good
conductor.... You stick a pizza in the oven and it gets hot... does this
mean pizza is a good conductor? All it means is that the pizza or CPU
substrate is in a hot place and therefore warms up... it does not mean that
either is good at transmitting heat from one place to another.
Anonymous
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August 21, 2004 1:58:03 AM

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"BigBadger" <big_badger@NOSPAM.com> wrote in message
news:cg5oin$4np$1@news7.svr.pol.co.uk...
> > Now, given that the cpu thermistor is on the other side of the substrate
> > on the botom of the cpu and is registering quite a high temp, and that
the
> > cpu electrical traces (which permeate the substrate) most definitely are
> > significant thermal conductors, it seems very reasonable to me to
conclude
> > that the opportunity is there to lower temps by this multiplication of
the
> > surface area touched by the waterblock by probably 7x or 8x.

> Just because the substrate gets hot on the back does not mean it's a good
> conductor.... You stick a pizza in the oven and it gets hot... does this
> mean pizza is a good conductor? All it means is that the pizza or CPU
> substrate is in a hot place and therefore warms up... it does not mean
that
> either is good at transmitting heat from one place to another.

Uhm... If you touch somthing and it feels warm/hot then it IS conducting
heat and putting a sink on it will help keep it cool.

....and dont forget that there were some ceramic CPU's that would really
benefit from sinking the whole top of the CPU instead of just the core.
Anonymous
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a b K Overclocking
August 21, 2004 1:58:04 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

Noozer wrote:

> "BigBadger" <big_badger@NOSPAM.com> wrote in message
> news:cg5oin$4np$1@news7.svr.pol.co.uk...
>
>>>Now, given that the cpu thermistor is on the other side of the substrate
>>>on the botom of the cpu and is registering quite a high temp, and that
>
> the
>
>>>cpu electrical traces (which permeate the substrate) most definitely are
>>>significant thermal conductors, it seems very reasonable to me to
>
> conclude
>
>>>that the opportunity is there to lower temps by this multiplication of
>
> the
>
>>>surface area touched by the waterblock by probably 7x or 8x.
>
>
>>Just because the substrate gets hot on the back does not mean it's a good
>>conductor.... You stick a pizza in the oven and it gets hot... does this
>>mean pizza is a good conductor? All it means is that the pizza or CPU
>>substrate is in a hot place and therefore warms up... it does not mean
>
> that
>
>>either is good at transmitting heat from one place to another.
>
>
> Uhm... If you touch somthing and it feels warm/hot then it IS conducting
> heat and putting a sink on it will help keep it cool.

I'm afraid that what you're trying to imply isn't true. Yes, the chip
carrier gets hot and yes, you can cool IT. Unfortunately, that doesn't do
squat for cooling the CPU: the thing of concern.

>
> ...and dont forget that there were some ceramic CPU's that would really
> benefit from sinking the whole top of the CPU instead of just the core.

An impossible 'comparison' since you can't cool 'just the core' of an
enclosed ceramic CPU. But you'd be miles ahead of the game if you could.
Anonymous
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August 21, 2004 2:34:24 AM

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*****Replace 'NOSPAM' with 'btinternet' in the reply address*****
"Noozer" <dontspam@me.here> wrote in message
news:EQtVc.163163$J06.50963@pd7tw2no...
>
> "BigBadger" <big_badger@NOSPAM.com> wrote in message
> news:cg5oin$4np$1@news7.svr.pol.co.uk...
>> > Now, given that the cpu thermistor is on the other side of the
>> > substrate
>> > on the botom of the cpu and is registering quite a high temp, and that
> the
>> > cpu electrical traces (which permeate the substrate) most definitely
>> > are
>> > significant thermal conductors, it seems very reasonable to me to
> conclude
>> > that the opportunity is there to lower temps by this multiplication of
> the
>> > surface area touched by the waterblock by probably 7x or 8x.
>
>> Just because the substrate gets hot on the back does not mean it's a good
>> conductor.... You stick a pizza in the oven and it gets hot... does this
>> mean pizza is a good conductor? All it means is that the pizza or CPU
>> substrate is in a hot place and therefore warms up... it does not mean
> that
>> either is good at transmitting heat from one place to another.
>
> Uhm... If you touch somthing and it feels warm/hot then it IS conducting
> heat and putting a sink on it will help keep it cool.
>
> ...and dont forget that there were some ceramic CPU's that would really
> benefit from sinking the whole top of the CPU instead of just the core.

yeah, everything conducts heat to some extent but not everything is a 'good
conductor'..... Athlon XP's (which is what we are referring to) do not have
ceramic substrates. The substrate on an XP is some form of resin, while I
accept does conduct heat it does not do it very well. I'd hazard a guess
that it conducts orders of magnitude less well than the copper/aluminium of
the heatsink that is in direct contact with the CPU and therefore the
quantity of heat that would take the substrate>shim>heatsink path in favour
of the easier direct path to the heatsink is very very small.
Anonymous
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a b K Overclocking
August 21, 2004 5:04:16 AM

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"rms" <rsquires@flashREMOVE.net> wrote in message
news:Z4hVc.300$l%2.0@newssvr15.news.prodigy.com...

"Ok, my gut feeling was that installing a copper shim was a mod that could
provide measurable benefits...."

Is this a shim to help keep the water block level or a shim to spread the
heat from the core to a larger area? If it is a copper plate to spread the
core heat to a larger area, what good is it unless your water block is not
copper, and then it should be 10 mm or so thick.

I think you have some question but not a definitive answer.

--
Phil Weldon, pweldonatmindjumpdotcom
For communication,
replace "at" with the 'at sign'
replace "mindjump" with "mindspring."
replace "dot" with "."

"rms" <rsquires@flashREMOVE.net> wrote in message
news:Z4hVc.300$l%2.0@newssvr15.news.prodigy.com...
> Ok, my gut feeling was that installing a copper shim was a mod that could
> provide measurable benefits. My reasoning was as follows: Presently my
> Maze3 waterblock is only slightly warm at the edges of the block,
indicating
> a large thermal gradient between the center water channel and the outer
> water channel, and thus plenty of cooling power still available if some
heat
> could be diverted to the outer portion of the waterblock, instead of
simply
> the 1cm x 1.5cm cpu core area (non-heat-spreader cpu).
>
> Now, given that the cpu thermistor is on the other side of the substrate
on
> the botom of the cpu and is registering quite a high temp, and that the
cpu
> electrical traces (which permeate the substrate) most definitely are
> significant thermal conductors, it seems very reasonable to me to conclude
> that the opportunity is there to lower temps by this multiplication of the
> surface area touched by the waterblock by probably 7x or 8x.
>
> So. On my AthlonXP 1700+ running at 10.5 x 230fsb = 2.4ghz @ 1.9v cpu, I
> installed a copper shim from www.1coolpc.com (I bought the XP shim, but it
> required a lot of Dremel work to get it to fit -- I suspect this is
> actually a Barton shim; but anyway). I was very careful to check that the
> shim did not sit higher than the cpu core, to file all edges smooth, and
to
> check that the shim sat completely flat on the cpu substrate. In
addition,
> and this is an important touch, I smeared both sides of the shim with
> ArticSilver5, a thin coat. Don't get careless and blow off this step as
you
> will compromise much of the effectiveness of the mod.
>
> The results are extremely satisfying!! Immediately after installation
> Prime95 has stabilized at 54C, probably 10C lower than previous, and after
> curing will certainly drop even farther. Now, I hear the skeptics
scoffing,
> and realize that it's likely the thermal characteristics of the copper
shim
> are not the only factor for the dramatic improvement.
>
> I suspect that other factor consists of the large-surface-area copper shim
> forcing the (large and heavy) waterblock to lie completely flat on the cpu
> core. Although I've always used a fiber washer, clearly it was not
> preventing a slight rocking of the heatsink from one side of the core to
the
> other, which could be caused by unequal spring pressure or simply gravity.
>
> Both of these factors make the copper shim a must-have addition to a
> high-performance Barton or other non-heatspreader-type cpu installation,
> IMHO. There is no doubt in my mind that people running very heavy
heatsinks
> like the SP-97 or big waterblocks will see an immediate temperature
> reduction from careful installation of a copper shim.
>
> rms
>
>
Anonymous
a b à CPUs
a b K Overclocking
August 21, 2004 5:11:56 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

"BigBadger" <big_badger@NOSPAM.com> wrote in message
news:cg5qmp$jfm$1@news5.svr.pol.co.uk...
"... I'd hazard a guess that it conducts orders of magnitude less well than
the copper/aluminium of the heatsink that is in direct contact with the CPU
and therefore the quantity of heat that would take the
substrate>shim>heatsink path in favour of the easier direct path to the
heatsink is very very small."

The resin is probably more than THREE orders of magnitude less conductive,
and the quanity of heat taking that route is thus very very very very very
very very very small B^)

--
Phil Weldon, pweldonatmindjumpdotcom
For communication,
replace "at" with the 'at sign'
replace "mindjump" with "mindspring."
replace "dot" with "."


"BigBadger" <big_badger@NOSPAM.com> wrote in message
news:cg5qmp$jfm$1@news5.svr.pol.co.uk...
> *****Replace 'NOSPAM' with 'btinternet' in the reply address*****
> "Noozer" <dontspam@me.here> wrote in message
> news:EQtVc.163163$J06.50963@pd7tw2no...
> >
> > "BigBadger" <big_badger@NOSPAM.com> wrote in message
> > news:cg5oin$4np$1@news7.svr.pol.co.uk...
> >> > Now, given that the cpu thermistor is on the other side of the
> >> > substrate
> >> > on the botom of the cpu and is registering quite a high temp, and
that
> > the
> >> > cpu electrical traces (which permeate the substrate) most definitely
> >> > are
> >> > significant thermal conductors, it seems very reasonable to me to
> > conclude
> >> > that the opportunity is there to lower temps by this multiplication
of
> > the
> >> > surface area touched by the waterblock by probably 7x or 8x.
> >
> >> Just because the substrate gets hot on the back does not mean it's a
good
> >> conductor.... You stick a pizza in the oven and it gets hot... does
this
> >> mean pizza is a good conductor? All it means is that the pizza or CPU
> >> substrate is in a hot place and therefore warms up... it does not mean
> > that
> >> either is good at transmitting heat from one place to another.
> >
> > Uhm... If you touch somthing and it feels warm/hot then it IS conducting
> > heat and putting a sink on it will help keep it cool.
> >
> > ...and dont forget that there were some ceramic CPU's that would really
> > benefit from sinking the whole top of the CPU instead of just the core.
>
> yeah, everything conducts heat to some extent but not everything is a
'good
> conductor'..... Athlon XP's (which is what we are referring to) do not
have
> ceramic substrates. The substrate on an XP is some form of resin, while I
> accept does conduct heat it does not do it very well. I'd hazard a guess
> that it conducts orders of magnitude less well than the copper/aluminium
of
> the heatsink that is in direct contact with the CPU and therefore the
> quantity of heat that would take the substrate>shim>heatsink path in
favour
> of the easier direct path to the heatsink is very very small.
>
>
Anonymous
a b à CPUs
a b K Overclocking
August 21, 2004 10:02:41 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

One way to settle this silly argument might be for others
to chip in with more data points ... so here's mine.

I did this with a system I can afford to lose if I botch
things: homemade system with an Athlon XP 2400+ on a
Asus A7N266-VM motherboard. Stock AMD heatsink/fan combo.
Not overclocked: 2 GHz = 15 x 133 MHz.

Temp's before and after adding a "copper cpu shim" (details
below.) Temperatures as reported by Asus PC Probe.

Before After
Idle temp: 36'C 35'C
Prime95 temp: 52'C 51'C

In other words, NO SIGNIFICANT CHANGE.

Ambient room temp was 22'C for both tests.

Prime95 was used because that was what the OP said he used.

The "copper shim" was cut from a sheet of jeweller's copper.
The results above were for 0.3 mm copper. I also tried
0.5 mm copper, but the additional thickness prevented me
from being able to clamp the heatsink down. And no, those
are not exact thicknesses - that is just the limits of the
accuracy of the cheap calipers I have at home.

In order to try to simulate the OP's setup, I also used
Arctic Silver on both sides of the shim - except it was
AS3 in my case because that is what I happened to have on
hand.




--
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Anonymous
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a b K Overclocking
August 21, 2004 10:02:42 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

Rob Stow wrote:

> One way to settle this silly argument might be for others
> to chip in with more data points ... so here's mine.
>
> I did this with a system I can afford to lose if I botch
> things: homemade system with an Athlon XP 2400+ on a
> Asus A7N266-VM motherboard. Stock AMD heatsink/fan combo.
> Not overclocked: 2 GHz = 15 x 133 MHz.
>
> Temp's before and after adding a "copper cpu shim" (details
> below.) Temperatures as reported by Asus PC Probe.
>
> Before After
> Idle temp: 36'C 35'C
> Prime95 temp: 52'C 51'C
>
> In other words, NO SIGNIFICANT CHANGE.
>
> Ambient room temp was 22'C for both tests.
>
> Prime95 was used because that was what the OP said he used.
>
> The "copper shim" was cut from a sheet of jeweller's copper.
> The results above were for 0.3 mm copper. I also tried
> 0.5 mm copper, but the additional thickness prevented me
> from being able to clamp the heatsink down. And no, those
> are not exact thicknesses - that is just the limits of the
> accuracy of the cheap calipers I have at home.
>
> In order to try to simulate the OP's setup, I also used
> Arctic Silver on both sides of the shim - except it was
> AS3 in my case because that is what I happened to have on
> hand.

Your results are equal within measurement error and what one would expect
from the physics of it.
Anonymous
a b à CPUs
a b K Overclocking
August 21, 2004 5:46:23 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

On Sat, 21 Aug 2004 06:02:41 GMT, Rob Stow <rob.stow.nospam@shaw.ca>
wrote:

>Temp's before and after adding a "copper cpu shim" (details
>below.) Temperatures as reported by Asus PC Probe.

Let's put it this way, when somebody discovered grounding the heatsink
was going to give them a few tens Mhz in overclocks, even I heard
about it as it filtered through sites and online forums.

Copper shims aren't new especially before AMD started putting them
pads on the chip. If it can bring down temperature in any significant
way, I'm pretty sure them overclockers sites would had been onto it a
long while ago! :p pP

I'm of the opinion the originator probably didn't seat his HSF
properly in the first place. 60+ degrees celsius is pretty hot for
even an older XP. I had one and even at overclocked speeds with the
default heatsink and TIM, it was only in the high 50s. Full load with
my generally warm local ambient, no airconditioning.
--
L.Angel: I'm looking for web design work.
If you need basic to med complexity webpages at affordable rates, email me :) 
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But keep in mind you pay extra bandwidth for their bloated code
Anonymous
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a b K Overclocking
August 21, 2004 5:49:47 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

BigBadger wrote:
> Noozer wrote:
>>
[...]
>>
>> Uhm... If you touch somthing and it feels warm/hot then it IS
>> conducting heat and putting a sink on it will help keep it cool.

Depending on how you mean this, this is either very true or complete
bollocks :)  Something "feels hot" if it conducts heat to your
hands/foot/whatever. In other words, the material you're touching is hotter
than your hand. However, this does not imply anything about how the material
is conducting heat to other destinations. For example, consider the
following system:
Ice ----- ceramic ----- copper bar ----- heat source
0 deg C ----- 18.8 deg C/W ----- 0.2 deg C/W ----- 200 deg C
(just making up numbers here). If you touch the copper bar, it will feel
hot, and you will get burnt. However, the bar will be conducting very little
heat. Why? Well., the total thermal resistance from the source to the water
is 20 deg C/W. So for the 200 deg C temperature delta, you get 10W of heat
flowing through the system. Hence at 0.2 deg C/W, the left had side of the
copper bar will be 200 - 2 = 198 deg C (with a linear gradient along it).

An somewhat related fact ... you can carry around shuttle heatshield plates
that are at close to 1000 deg C (internally) with your bare hands. They're
very hot, but their thermal resistance is so high that, after an initial
(very short) period where the top fraction of a mm cools, essentially no
heat is conducted to your hands (ie: you don't get burnt). I had an awesome
picture of this being demonstrated but I can't seem to find it any more.
However, at
http://www-pao.ksc.nasa.gov/kscpao/nasafact/tps.htm
There is the quote:
"Surface heat dissipates so quickly that a tile can be held by its corners
with a bare hand only seconds after removal from a 2,300 degrees F oven,
while the center of the tile still glows red with heat."

So, getting back to the topic :)  , If you touch thte substrate and it feels
hot, then all you can say is that the material is hot. if the temperature is
close to the source temperature, then this implies that there's a higher
thermal resistance to a heat sink compared to the resistance to the heat
source.

>> ...and dont forget that there were some ceramic CPU's that would
>> really benefit from sinking the whole top of the CPU instead of just
>> the core.
>
> yeah, everything conducts heat to some extent but not everything is a
> 'good conductor'..... Athlon XP's (which is what we are referring to)
> do not have ceramic substrates. The substrate on an XP is some form
> of resin, while I accept does conduct heat it does not do it very
> well.

The thermal conductivity of the packaging is quite complex, since it's a
layered material, and each layer is actually broken up into a number of
areas by the tracing. The vertical thermal resistance should be fairly high
as there are quite a few interfaces that it needs to pass through, and a lot
of the distance travelled is through substrate. I suspect the horizontal
thermal resistance would be quite high as well, since a lot of the copper
groundplate in in a honeycomb form, and the traces are quite small. See
http://hill195.home.mchsi.com/Locked/carcass.jpg
(warning: link contains a graphic image of a mutilated CPU)
for details.

> I'd hazard a guess that it conducts orders of magnitude less
> well than the copper/aluminium of the heatsink that is in direct
> contact with the CPU and therefore the quantity of heat that would
> take the substrate>shim>heatsink path in favour of the easier direct
> path to the heatsink is very very small.

The rough back-of-the-envelope calculations I did before showed that,
assuming the entire temperature difference was due to conduction through the
shim as opposed to improved mounting, the thermal resistance of the shim
path would have to be around 2.5 deg C/W (as opposed to about 0.6 deg C/W
for the direct path). This is the die->water thermal resistance btw. IMO
this is unlikely, so at least some of the difference would have come through
mounting improvements. Whether this was due to poor initial mounting or
general improved mounting due to the shim is not possible to say without
doing a few more remountings.

--
Michael Brown
www.emboss.co.nz : OOS/RSI software and more :) 
Add michael@ to emboss.co.nz - My inbox is always open
Anonymous
a b à CPUs
a b K Overclocking
August 21, 2004 8:34:16 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

The little lost angel wrote:

> On Sat, 21 Aug 2004 06:02:41 GMT, Rob Stow <rob.stow.nospam@shaw.ca>
> wrote:
>
>
>>Temp's before and after adding a "copper cpu shim" (details
>>below.) Temperatures as reported by Asus PC Probe.
>
>
> Let's put it this way, when somebody discovered grounding the heatsink
> was going to give them a few tens Mhz in overclocks, even I heard
> about it as it filtered through sites and online forums.
>
> Copper shims aren't new especially before AMD started putting them
> pads on the chip. If it can bring down temperature in any significant
> way, I'm pretty sure them overclockers sites would had been onto it a
> long while ago! :p pP

I think what people are trying to do with shims is
to emulate what some of the copper/aluminum heatsinks
do. The sinks with a copper bottom and aluminum fins
use copper's better thermal transport capability to do
a better job of moving heat to the outer fins so that
those fins contribute more towards cooling the cpu.
Some copper-based/aluminum finned sinks also have a heat
pipe in the copper base to help with this.

However, when you use a shim you probably negate any
such heat transport benefit because instead of having
a single layer of thermal compound between the cpu
and the sink, you now have three layers: compound,
shim, and compound.

> I'm of the opinion the originator probably didn't seat his HSF
> properly in the first place. 60+ degrees celsius is pretty hot for
> even an older XP. I had one and even at overclocked speeds with the
> default heatsink and TIM, it was only in the high 50s. Full load with
> my generally warm local ambient, no airconditioning.


--
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Anonymous
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a b K Overclocking
August 21, 2004 9:35:51 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

Rob Stow wrote:
> The little lost angel wrote:
>
>> On Sat, 21 Aug 2004 06:02:41 GMT, Rob Stow <rob.stow.nospam@shaw.ca>
>> wrote:
>>
>>
>>> Temp's before and after adding a "copper cpu shim" (details
>>> below.) Temperatures as reported by Asus PC Probe.
>>
>>
>>
>> Let's put it this way, when somebody discovered grounding the heatsink
>> was going to give them a few tens Mhz in overclocks, even I heard
>> about it as it filtered through sites and online forums.
>> Copper shims aren't new especially before AMD started putting them
>> pads on the chip. If it can bring down temperature in any significant
>> way, I'm pretty sure them overclockers sites would had been onto it a
>> long while ago! :p pP
>
>
> I think what people are trying to do with shims is
> to emulate what some of the copper/aluminum heatsinks
> do.


> The sinks with a copper bottom

Are doing what the integral heat spreader did.

> and aluminum fins
> use copper's better thermal transport capability to do
> a better job of moving heat to the outer fins so that
> those fins contribute more towards cooling the cpu.
> Some copper-based/aluminum finned sinks also have a heat
> pipe in the copper base to help with this.
>
> However, when you use a shim you probably negate any
> such heat transport benefit because instead of having
> a single layer of thermal compound between the cpu
> and the sink, you now have three layers: compound,
> shim, and compound.

The bigger reason is it isn't in contact with the core whereas the copper
bottom of the heat sink is and already doing what the integral heat
spreader did.

>> I'm of the opinion the originator probably didn't seat his HSF
>> properly in the first place. 60+ degrees celsius is pretty hot for
>> even an older XP. I had one and even at overclocked speeds with the
>> default heatsink and TIM, it was only in the high 50s. Full load with
>> my generally warm local ambient, no airconditioning.
>
>
>
Anonymous
a b à CPUs
a b K Overclocking
August 23, 2004 10:28:55 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

On Sat, 21 Aug 2004 16:34:16 GMT, Rob Stow <rob.stow.nospam@shaw.ca>
wrote:
>I think what people are trying to do with shims is
>to emulate what some of the copper/aluminum heatsinks
>do. The sinks with a copper bottom and aluminum fins
>use copper's better thermal transport capability to do
>a better job of moving heat to the outer fins so that
>those fins contribute more towards cooling the cpu.
>Some copper-based/aluminum finned sinks also have a heat
>pipe in the copper base to help with this.

That doesn't make much sense even if we ignore the point about there
being triple layers of compound/shim/compound to go through. One of
the key thing for the heatsink to work properly is strong pressure
pushing the sink and chip together. What's going to be pushing the
shim tight against the side of the core? If there's no way to get a
proper tight contact with the shim against the core, it would be
useless to transport heat away from the core. The packaging sure
doesn't conduct much heat since I know I can touch the package way
before it's not painful to touch the core :p pPp

--
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Anonymous
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a b K Overclocking
August 23, 2004 10:58:34 AM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

The little lost angel wrote:

> On Sat, 21 Aug 2004 16:34:16 GMT, Rob Stow <rob.stow.nospam@shaw.ca>
> wrote:
>
>>I think what people are trying to do with shims is
>>to emulate what some of the copper/aluminum heatsinks
>>do. The sinks with a copper bottom and aluminum fins
>>use copper's better thermal transport capability to do
>>a better job of moving heat to the outer fins so that
>>those fins contribute more towards cooling the cpu.
>>Some copper-based/aluminum finned sinks also have a heat
>>pipe in the copper base to help with this.
>
>
> That doesn't make much sense even if we ignore the point about there
> being triple layers of compound/shim/compound to go through. One of
> the key thing for the heatsink to work properly is strong pressure
> pushing the sink and chip together. What's going to be pushing the
> shim tight against the side of the core?

The shim I experimented with was the exact size and shape
as the bottom of the heatsink. Putting the shim in contact
with the core is no different and no more difficult than
putting the bottom of a heatsink in contact with the core.

And because you are squeezing the shim between the heatsink
and the processor, there is actually more pressure - as is
evidenced by the increased difficulty in clamping the heatsink
down. Crushing the core or breaking the socket becomes a
significant risk.

Wish I had a camera. A pictures is worth a thousand
word, as the thriving porn industry amply demonstrates.


> If there's no way to get a
> proper tight contact with the shim against the core, it would be
> useless to transport heat away from the core. The packaging sure
> doesn't conduct much heat since I know I can touch the package way
> before it's not painful to touch the core :p pPp

Contact with the packaging is irrelevant here.
The copper shim is used to more evenly distribute heat
from the core across the bottom of the aluminum heatsink.


And, of course, if the bottom of your heatsink is already
copper, then there is absolutely no point in trying this
silly experiment.


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Anonymous
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a b K Overclocking
August 23, 2004 5:12:13 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

In comp.sys.ibm.pc.hardware.chips The little lost angel <a?n?g?e?l@lovergirl.lrigrevol.moc.com> wrote:
> That doesn't make much sense even if we ignore the point about
> there being triple layers of compound/shim/compound to go
> through. One of the key thing for the heatsink to work properly
> is strong pressure pushing the sink and chip together.

The pressure is there to squeeze the thermal compound as thin
as possible. Both joints need to be good (thin and bubble-free)

> What's going to be pushing the shim tight against the
> side of the core?

I don't think there's much need to contact the die edge.

> If there's no way to get a proper tight contact with the
> shim against the core, it would be useless to transport heat
> away from the core.

As I read it, the shim is sandwiched between the core and heatsink.
You don't want the shim near the package and those exposed jumpers
or caps. It basically makes up for a somewhat poorly designed HS
(too thin a base). Lateral heat transfer matters.

> The packaging sure doesn't conduct much heat since I know I can touch
> the package way before it's not painful to touch the core :p pPp

True enough.

-- Robert
Anonymous
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a b K Overclocking
August 23, 2004 5:12:14 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

Robert Redelmeier wrote:

> In comp.sys.ibm.pc.hardware.chips The little lost angel <a?n?g?e?l@lovergirl.lrigrevol.moc.com> wrote:
>
>>That doesn't make much sense even if we ignore the point about
>>there being triple layers of compound/shim/compound to go
>>through. One of the key thing for the heatsink to work properly
>>is strong pressure pushing the sink and chip together.
>
>
> The pressure is there to squeeze the thermal compound as thin
> as possible. Both joints need to be good (thin and bubble-free)
>
>
>>What's going to be pushing the shim tight against the
>>side of the core?
>
>
> I don't think there's much need to contact the die edge.
>
>
>>If there's no way to get a proper tight contact with the
>>shim against the core, it would be useless to transport heat
>>away from the core.
>
>
> As I read it, the shim is sandwiched between the core and heatsink.

Unless he's doing something really strange it's a commonly available 'shim'
that sits on the chip carrier and not between the core and heatsink.

> You don't want the shim near the package and those exposed jumpers
> or caps.

The typical 'pre-made' shim is cutout around those areas to provide clearance.

> It basically makes up for a somewhat poorly designed HS
> (too thin a base).

Wishful thinking.

> Lateral heat transfer matters.

What you're thinking would, at least, have a chance if you were talking
about an 1/8 inch think, or so, copper plate instead of an .027 inch thin
'shim' that could never be keep flat and in pressure contact across the
heatsink base. But, then, you wouldn't have a rat's chance in hell of
attaching the spring clip with a 1/8 inch plate under the base even after
the core was crushed flat.

>>The packaging sure doesn't conduct much heat since I know I can touch
>>the package way before it's not painful to touch the core :p pPp
>
>
> True enough.
>
> -- Robert
>
Anonymous
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a b K Overclocking
August 23, 2004 7:33:33 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

In comp.sys.ibm.pc.hardware.chips David Maynard <dNOTmayn@ev1.net> wrote:
>> As I read it, the shim is sandwiched between the core and heatsink.

> Unless he's doing something really strange it's a commonly
> available 'shim' that sits on the chip carrier and not
> between the core and heatsink.

Why would anyone manufacture such a useless and potentially
dangerous thing? The chip carrier has very poor thermal
conductivity and you're never going to get the thickness
right. Either a too thick carrier will prevent die-contact
(horrors!) or a thin carrier won't contact the package (doing
no good).


> What you're thinking would, at least, have a chance if you
> were talking about an 1/8 inch think, or so, copper plate

Yes, that's what I thought. Nice slug of copper 3-4 mm thick,
shipped with a new bale or attachment mechanism to accommodate
the extra thickness.

The OP saw some improvement -- it must have been from a flatter
HS contact. I suspect s/he must have put the HSF on backwards,
or received an HSF with the bale switched.

-- Robert
Anonymous
a b à CPUs
a b K Overclocking
August 23, 2004 11:16:34 PM

Archived from groups: alt.comp.hardware.overclocking.amd,alt.comp.hardware.overclocking,comp.sys.ibm.pc.hardware.chips (More info?)

Robert Redelmeier wrote:
> In comp.sys.ibm.pc.hardware.chips David Maynard <dNOTmayn@ev1.net> wrote:
>
>>>As I read it, the shim is sandwiched between the core and heatsink.
>
>
>>Unless he's doing something really strange it's a commonly
>>available 'shim' that sits on the chip carrier and not
>>between the core and heatsink.
>
>
> Why would anyone manufacture

The original reason was the Athlon's tendency to get cracked cores from
heatsinks being 'rocked' on during installation. AMD responded by adding
rubber bumpers.

Then someone, long time before now, got the not very well thought out idea:
hey, if it's copper then maybe...

> such a useless and potentially
> dangerous thing? The chip carrier has very poor thermal
> conductivity and you're never going to get the thickness
> right. Either a too thick carrier will prevent die-contact
> (horrors!) or a thin carrier won't contact the package (doing
> no good).


That's been the point of the critiques.


>>What you're thinking would, at least, have a chance if you
>>were talking about an 1/8 inch think, or so, copper plate
>
>
> Yes, that's what I thought. Nice slug of copper 3-4 mm thick,
> shipped with a new bale or attachment mechanism to accommodate
> the extra thickness.

There's a chance with a new bail but then not all heatsinks use the same
physical configuration so it's virtually impossible to make a 'universal' one.

The upshot is it's better to simply get a proper heatsink to begin with.


> The OP saw some improvement -- it must have been from a flatter
> HS contact. I suspect s/he must have put the HSF on backwards,
> or received an HSF with the bale switched.

That's been the general speculation.
!