A computer components & hardware forum. HardwareBanter

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » HardwareBanter forum » Processors » Overclocking AMD Processors
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Copper Shims - Any good



 
 
Thread Tools Display Modes
  #1  
Old June 27th 04, 08:46 PM
Alex
external usenet poster
 
Posts: n/a
Default Copper Shims - Any good

Is it worth getting a copper shim for my AMD XP when I fit a new
cooler? What exactly do they do?

TIA

Alex
  #2  
Old June 27th 04, 08:49 PM
Alex
external usenet poster
 
Posts: n/a
Default

I wouldn't bother. They're meant to "prevent" the core from being crushed
due to too much pressure from the heatsink. I've never experienced this on
any of the systems I've built.


"Alex" wrote in message
...
Is it worth getting a copper shim for my AMD XP when I fit a new
cooler? What exactly do they do?

TIA

Alex



  #3  
Old June 27th 04, 08:56 PM
REMUS
external usenet poster
 
Posts: n/a
Default

"Alex" wrote in message
...
Is it worth getting a copper shim for my AMD XP when I fit a new
cooler? What exactly do they do?

TIA

Alex



I wouldn't bother. They're meant to "prevent" the core from being crushed
due to too much pressure from the heatsink. I've never experienced this

on
any of the systems I've built.


Yeah your really only in any danger of crushing the core if you have a screw
on heatsink.


  #4  
Old June 28th 04, 01:17 AM
rms
external usenet poster
 
Posts: n/a
Default

I wouldn't bother. They're meant to "prevent" the core from being crushed
due to too much pressure from the heatsink.


You are neglecting the potential additional heat transfer of cpu heat
from the substrate to the heatsink with a copper shim. If you were careful
in coating both sides of the shim with compound, I wouldn't be at all
surprised to see say 1-2C temperature difference from a shim-less install.
Small of course, but so what? Small differences make tinkering with such
simple mods fun.

rms


  #5  
Old June 28th 04, 02:06 AM
Michael Brown
external usenet poster
 
Posts: n/a
Default

rms wrote:
I wouldn't bother. They're meant to "prevent" the core from being
crushed due to too much pressure from the heatsink.


You are neglecting the potential additional heat transfer of cpu
heat from the substrate to the heatsink with a copper shim.


Actually, it's the reverse. The substrate has a much higher thermal
resistance compared to copper (or aluminium), so at any particular point on
the substrate, the HSF surface above it has a higher temperature. So you'd
actually be dumping heat back into the substrate, though in any case there
isn't much conduction/convection away from the substrate, so there would be
a negligible performance difference.

[...]

--
Michael Brown
www.emboss.co.nz : OOS/RSI software and more
Add michael@ to emboss.co.nz - My inbox is always open


  #6  
Old June 28th 04, 03:12 AM
rms
external usenet poster
 
Posts: n/a
Default

you'd
actually be dumping heat back into the substrate


Interesting theory, but I'm not sure I buy it, especially in the case of
a water-cooled system like mine. I can touch the perimeter of my waterblock
under full load, and it is essentially the water temperature. In other
words there is a significant temperature gradient between the outer and
inner areas of the waterblock surface, and I would imagine this gradient is
much steeper than for the average air-cooled sink, given the poor heat
removing capacity of air vs that of water.

The purpose of the copper shim is to increase contact from the substrate to
the outer area of the waterblock surface, which in this scenario is quite
likely to be cooler than the substrate, thus removing additional heat, not
adding it.

Also, in the ideal situation, with a more or less perfect heatsink that
instantly removes all heat without spreading it out over the heatsink
surface, it should be clear that more surface area equals more heat removal.
So the better the heatsink, the more a cpu copper shim should help. That's
my argument anyway.

No, I haven't tried a copper shim yet, tho I have bought one and have been
meaning to try it out, along with doing a simple waterblock mod and using
larger fans on my radiator.

rms


  #7  
Old June 28th 04, 06:05 AM
Michael Brown
external usenet poster
 
Posts: n/a
Default

rms wrote:
you'd
actually be dumping heat back into the substrate


Interesting theory, but I'm not sure I buy it, especially in the
case of a water-cooled system like mine.


Ah, yes, I should have been a little more specific In most air-cooled
systems, the horozontal gradient is relatively low on the bottom of the HSF,
with a steep gradient right near the edge (where there is significant air
circulation and whirlpooling). This is primarily due to the dead area of air
circulation above the HSF base. The main temperature gradient is vertical in
these cases. I saw some thermal imaging camera pics of this somewhere
(LostCircuits I thought) but I don't have any links on me at the moment.
Waterblocks and (some) non-standard HSF designs get around this.

For a well-designed waterblock, you can effectively treat the inside surface
as being at water temperature. This means that the horozontal gradient is
very steep (as is the vertical gradient as you've only got a few mm of
copper between the heat source and the inner surface), and hence the shim
would actually help cooling as long as it didn't reduce the pressure, etc
between the block and the die. I still don't think it would be particularily
great, as the thermal resistance of the substrate is relatively high, but it
would probably drop your substrate temps (ie: socket temps) and make you
feel a bit better It'd be interesting to see what it would do for die
temps (though repeated installation and removal of the shim would be
necessary to get some idea of the standard error of the measurements created
from WB installation variations).

[...]
Also, in the ideal situation, with a more or less perfect heatsink
that instantly removes all heat without spreading it out over the
heatsink surface, it should be clear that more surface area equals
more heat removal. So the better the heatsink, the more a cpu copper
shim should help. That's my argument anyway.


Agreed

[...]

--
Michael Brown
www.emboss.co.nz : OOS/RSI software and more
Add michael@ to emboss.co.nz - My inbox is always open


  #8  
Old June 28th 04, 09:08 PM
Ben Pope
external usenet poster
 
Posts: n/a
Default

Alex wrote:
Is it worth getting a copper shim for my AMD XP when I fit a new
cooler? What exactly do they do?


No, since most chims are designed for the TBreds and you could end up
crushing or shorting some of the components on the chip. (which are in a
different configuration on the XPs)

They are there to help prevent you from damaging your CPU, but if you are
such a vandal and so careless that you need to use shims to protect your CPU
then you shouldn;t be doing the job in the first place.

Ben
--
A7N8X FAQ: www.ben.pope.name/a7n8x_faq.html
Questions by email will likely be ignored, please use the newsgroups.
I'm not just a number. To many, I'm known as a String...


  #9  
Old June 28th 04, 09:10 PM
Ben Pope
external usenet poster
 
Posts: n/a
Default

rms wrote:
I wouldn't bother. They're meant to "prevent" the core from being
crushed due to too much pressure from the heatsink.


You are neglecting the potential additional heat transfer of cpu heat
from the substrate to the heatsink with a copper shim.


Thermal resistance of the substrate is such that the heat transfer is
negligible anyway.

If you were
careful in coating both sides of the shim with compound, I wouldn't be at
all surprised to see say 1-2C temperature difference from a shim-less


Difference in the temperature of what?

install. Small of course, but so what? Small differences make tinkering
with such simple mods fun.



What about the reduction of air flow to the side of the core, and to the
substrate? Would that not have a negative effect on temps?

Ben
--
A7N8X FAQ: www.ben.pope.name/a7n8x_faq.html
Questions by email will likely be ignored, please use the newsgroups.
I'm not just a number. To many, I'm known as a String...


  #10  
Old June 30th 04, 06:32 AM
Christopher Rawlison
external usenet poster
 
Posts: n/a
Default


Michael Brown wrote:

rms wrote:

I wouldn't bother. They're meant to "prevent" the core from being
crushed due to too much pressure from the heatsink.


You are neglecting the potential additional heat transfer of cpu
heat from the substrate to the heatsink with a copper shim.



Actually, it's the reverse. The substrate has a much higher thermal
resistance compared to copper (or aluminium), so at any particular point on
the substrate, the HSF surface above it has a higher temperature. So you'd
actually be dumping heat back into the substrate, though in any case there
isn't much conduction/convection away from the substrate, so there would be
a negligible performance difference.


Actually, a shim does NOTHING for thermal transfer. Think about it this
way: when was the last time you felt the actual ceramic base on a chip?
It stays comparatively cool. Ceramic is a thermal insulator, which
means that it will keep heat from going from the silicon of the
processor to the rest of the packaging material. That means that the
heat has nowhere to go except to move into the heatsink. Also you
should be careful about putting any type of thermal interface material
on a shim that is conductive for the simple fact that XPs have bridges
on the ceramic that could get shorted by the TIM.

----------

To reply, replace 'deadfishies' with 'bigfoot.'

We live our life in our own way, never ever listen to what they say, the
kind of faith that never fades away, we are the True Believers!

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Anyone know a good deal on a good mp3 player? travel General 1 November 30th 04 11:51 PM
Which Wireless Option Is Good For Streaming Video? Jay Chan General 0 October 21st 04 04:32 PM
Are cpu shims worth using? Jim General 4 April 11th 04 04:10 PM
Help me pick out a good mobo to use with XP 2800+ Ben in TN Overclocking AMD Processors 3 February 7th 04 12:25 PM
Good 2500+ ? Thomas Andersson Overclocking AMD Processors 3 July 21st 03 04:10 PM


All times are GMT +1. The time now is 04:55 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 HardwareBanter.
The comments are property of their posters.