So what if thermal compound spreads?

"Conor" wrote in message
...
In article , says...

"QBall" wrote in message
...

And it's so thick, there's no metal-metal contact.

Thick? Like viscosity? Then you have bad paste for this application.

No. THick as in distance from one face to the other.

Then I'd like to understand how it's possible to get a "thick" layer when
the heatsink is applied properly, and with all the pressure from the clamps.

On Sun, 11 Apr 2004 20:26:53 +0100 As truth resonates honesty Lem
wrote :

Paul Hopwood wrote:

I realised he could have meant either, so asked for
elaboration. Actually some thermal compund is electrically
conductive too,

Any of the stuff that's filled with metallic particles is
potentially electrically conductive.

Please name one.

Arctic Silver is capacitive, rather than conductive, but the
same applies in terms of application. Their instructions
state:

"While much safer than electrically conductive silver and
copper greases, Arctic Silver should be kept away from
electrical traces, pins, and leads. While it is not
electrically conductive, the compound is slightly capacitive
and could potentially cause problems if it bridges two
close-proximity electrical paths.)"

I wouldn't doubt there are other compounds around which are
electrically conductive.


Hiya Paul. And now for something completely different .... Dan
compares toothpaste and Vegemite/Marmite to Artic Silver and finds
that both are actually better! At least they are until they dry
out.

http://www.dansdata.com/goop.htm

Dan is, of course, also the author of How To destroy Your Computer.
http://www.dansdata.com/sbs3.htm

I can believe it.There's lot's of Hype about.
I bought this cooler for my O/C AMD XP 1800,
MicroFlow2 SPA07B2 (Skt A)
http://tinyurl.com/ybtn

look at the price

and it came with it's own tube of,"Artic" silver.So the whole
kit-and-kaboodle was actually less than the cost one tube
of,"Genuine","Artic Silver".
Even under my heaviest gaming loads it rarely goes above 40 Deg C and
trust me I give my system,"Hammer".
I did polish the bottom of the HS but the copper centre really does
the biz anyway.

As we speak Idle temps are,

37 Deg C

Running @ 143/143


As summer comes I expect it to hit 50 Deg C,but then that's nowt for
an AMD and the ting is near silent as well

This has to be the bargain of the year IMNSHO :P



--
Free Windows/PC help,
http://www.geocities.com/sheppola/trouble.html
email shepATpartyheld.de
Free songs to download and,"BURN" :O)
http://www.soundclick.com/bands/8/nomessiahsmusic.htm

QBall wrote:
"Johannes H Andersen" wrote in message
...


Matt wrote:

Conor wrote:

In article ,
says...


CrackerJack wrote:


What exactly is the problem if too much cpu compound is put on the
core and it gets squashed out onto the surrounding area?

Apart from looking messy, is there any real problem with this?

I propose this answer:

1) If the compound is not too viscous, and the heatsink is clamped on
with some force, and you apply enough compound, the thickness of the
layer of compound does not depend on the amount applied, which is to

say

that the excess gets squeezed out.

2) Thermal compounds are not electrically conductive.

3) Some thermal compounds (notably those containing silver compounds)
have capacitative properties that can be problemmatic if compound gets
between the chip's leads.

4) If you use a compound that doesn't have the problemmatic

capacitative

properties and is not too viscous, in general it won't hurt to use too

much.


1) WRONG
2) WRONG
3) If 3 is true then 2) is wrong. You've just proved that yourself.
4) WRONG.


Your reply is practically content-free.

Please start with this: In what way does 3 contradict 2?

Apart from the above, the word you're looking for is 'dielectric'. Look
up any elementary physics text book.



Hehe ..... LOL
The contemporary edukation system has a lot to answer for.
Bad spelling is so freaking irritating.



Yeah, and don't you hate it when somebody replies and quotes a bunch of
material that is irrelevant to the point he is supposedly making?

My we are having a tiff here, I am surprised that what seemed such a
trival question could start WWIII. lol.

Anyway surely it doesnt matter that much u use as it must be a fairly
good conductor anyway.

Although if it is a good conductor you wouldn't want it dropping onto your
mobo.



"jeffc" wrote in message
...

"QBall" wrote in message
...


It is hard to judge the exact amount. Rather than put too little
on and run the risk of not conducting heat away from the core,


You clearly have no understanding of thermal transfer, which is
maximised
via metal-metal contact.
You fall into the ingenue's trap of believing more is better, when it
fact
less is more.

And you fall into the trap of not understanding what thermal paste is used
for in the first place. It doesn't matter how much TP you use. The
pressure of the clamps holding down the heatsink will press out all TP
possible, while maximizing metal-to-metal contact. There will be no more
and no less metal-to-metal contact whether you use TP or not. The only
difference TP makes is that everywhere there is NOT metal-to-metal
contact,
there will now be TP instead of air. If you use too little TP, you will
not
get optimal heat transfer. If you use exactly the right amount of TP
(impossible), you will get optimal heat transfer. If you use too much TP,
you will get optimal heat transfer. The layer will be the same after
pressure is applied.

"CrackerJack" wrote in message
...
What exactly is the problem if too much cpu compound is put on the
core and it gets squashed out onto the surrounding area?

Apart from looking messy, is there any real problem with this?

Prehaps this thread should be retitled "Much ado about nothing"?

jeffc wrote:
"QBall" wrote in message
...


It is hard to judge the exact amount. Rather than put too little
on and run the risk of not conducting heat away from the core,


You clearly have no understanding of thermal transfer, which is
maximised via metal-metal contact.
You fall into the ingenue's trap of believing more is better, when
it fact less is more.

And you fall into the trap of not understanding what thermal paste is
used for in the first place. It doesn't matter how much TP you use.
The pressure of the clamps holding down the heatsink will press out
all TP possible, while maximizing metal-to-metal contact. There will
be no more and no less metal-to-metal contact whether you use TP or
not. The only difference TP makes is that everywhere there is NOT
metal-to-metal contact, there will now be TP instead of air. If you
use too little TP, you will not get optimal heat transfer. If you
use exactly the right amount of TP (impossible), you will get optimal
heat transfer. If you use too much TP, you will get optimal heat
transfer. The layer will be the same after pressure is applied.

Nope. Thermal compund is nowhere near as good at conducting heat as
metal-metal contact. If you use too much, you`ll end up with fewer
metal-metal connections, and more heat having to go through the thermal
compund. Therefore less efficient cooling.

"Conor" wrote in message
...
In article , says...

If the goo squishes out then presumably the layer of goo is no
thicker or thinner than if it didn't squish out?

Wrong.


Not wrong

"Simon Finnigan" wrote in message
...

And you fall into the trap of not understanding what thermal paste is
used for in the first place. It doesn't matter how much TP you use.
The pressure of the clamps holding down the heatsink will press out
all TP possible, while maximizing metal-to-metal contact. There will
be no more and no less metal-to-metal contact whether you use TP or
not. The only difference TP makes is that everywhere there is NOT
metal-to-metal contact, there will now be TP instead of air. If you
use too little TP, you will not get optimal heat transfer. If you
use exactly the right amount of TP (impossible), you will get optimal
heat transfer. If you use too much TP, you will get optimal heat
transfer. The layer will be the same after pressure is applied.

Nope. Thermal compund is nowhere near as good at conducting heat as
metal-metal contact.

No one is denying that. If you thought that's what I said, you didn't read.

If you use too much, you`ll end up with fewer
metal-metal connections, and more heat having to go through the thermal
compund. Therefore less efficient cooling.

The pressure from the heatsink clamp will ensure that the layer is as thin
as possible, assuming the heatsink is applied properly.

On Mon, 12 Apr 2004 14:22:37 GMT, kony wrote:

On Mon, 12 Apr 2004 13:19:12 GMT, JT wrote:

I don't think he is referring to damage by static. I think there
is something "bad" about even a trace of grease like that from a
finger. I don't know why this is though.

Can anyone enlighten me (gently)?

Short term, skin oils are a poor heat conductor, so interfere with heat
transfer from cpu to heatsink. Long term most peoples skin oils are acidic
or salty enough to cause corrosion, which is also not a good thing to have
between a cpu and a heatsink

JT

Nonsense. NOBODY has enough oil on their fingers to significantly cause
corrosion or degrade the cooling efficiency. Now maybe if someone had
just finished picking their nose or painting a fence...

Simple experiment. Take a clean, shiny sheet of copper or brass. Make sure
it is clean. Use alcohol or the cleaner of your choice to ensure it is oil
free and clean. Now take your nice clean finger and touch the center of the
metal. Leave this metal somewhere that it won't be disturbed for a couple
weeks. See the discoloration? That is corrosion. That is enough to reduce
heat transfer, although not catastrophically. It is slow acting, but it
does happen. Doesn't take much corrosion to interfere with cooling. Because
it acts over time, it will take a while to cause a problem. Why take a
chance? Keep your fingers off the mating surface. If you are going to go to
the trouble of properly, why not keep your fingers out of the way.

BTW, some peoples skin oils are much more corrosive than others.

JT

jeffc wrote:
"Simon Finnigan" wrote in message
...

And you fall into the trap of not understanding what thermal paste
is used for in the first place. It doesn't matter how much TP you
use. The pressure of the clamps holding down the heatsink will
press out
all TP possible, while maximizing metal-to-metal contact. There
will be no more and no less metal-to-metal contact whether you use
TP or not. The only difference TP makes is that everywhere there
is NOT metal-to-metal contact, there will now be TP instead of air.
If you use too little TP, you will not get optimal heat transfer.
If you
use exactly the right amount of TP (impossible), you will get
optimal heat transfer. If you use too much TP, you will get
optimal heat transfer. The layer will be the same after pressure
is applied.

Nope. Thermal compund is nowhere near as good at conducting heat as
metal-metal contact.

No one is denying that. If you thought that's what I said, you
didn't read.

If you use too much, you`ll end up with fewer
metal-metal connections, and more heat having to go through the
thermal compund. Therefore less efficient cooling.

The pressure from the heatsink clamp will ensure that the layer is as
thin as possible, assuming the heatsink is applied properly.

I think you`re just blindly assuming that the heat sink is squeezing out
every possible bit of the TP - have you got any evidence to cite proving
this assumption? I seriously doubt the small forces involved here - 40/50
pounds IIRC - are anywhere near enough to be certain of this.