COPPER CPU SHIMS: The Definitive Answer !!

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

In comp.sys.ibm.pc.hardware.chips rms 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

*****Replace 'NOSPAM' with 'btinternet' in the reply address*****
"rms" wrote in message
m...
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.

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.

"BigBadger" wrote in message
...
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.

*****Replace 'NOSPAM' with 'btinternet' in the reply address*****
"Noozer" wrote in message
news:EQtVc.163163$J06.50963@pd7tw2no...

"BigBadger" wrote in message
...
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 substrateshimheatsink path in favour
of the easier direct path to the heatsink is very very small.

Noozer wrote:

"BigBadger" wrote in message
...

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.

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.

"rms" wrote in message
...

"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" wrote in message
...
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

"BigBadger" wrote in message
...
"... 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
substrateshimheatsink 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" wrote in message
...
*****Replace 'NOSPAM' with 'btinternet' in the reply address*****
"Noozer" wrote in message
news:EQtVc.163163$J06.50963@pd7tw2no...

"BigBadger" wrote in message
...
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 substrateshimheatsink path in
favour
of the easier direct path to the heatsink is very very small.