Thermal pad or Thermal paste?

Strontium wrote:
-
David Maynard stood up at show-n-tell, in , and
said:


Arthur Hagen wrote:

"AnthonyR" wrote in message
...


What do you mean the chemist didn't have alcohol?


Vin said that the chemists said they didn't have *isopropyl* alcohol
(isopropanol). Alcohol is at least a dozen different things, from
methanol
to glycerin.

(Also note that when he said chemist, he almost certainly meant what
we call
a drugstore here in the US.)



Do you not have rubbing alcohol in your house? here in the states
every
house has a bottle, its used to clean wounds and stuff.


We sure don't have a bottle. Is it mandatory?



What do you use for scraped knee's?


Iodine tinctures, witch hazel, hydrogen peroxide, antibacterial
salves and lotions, or a whole lot of other stuff. Including other
alcohols. Using isopropanol as rubbing alcohol might be a regional
thing, because I'm used
to ethanol.

Denatured Alcohol vs. Isopropanol

Denatured Alcohol is ethyl alcohol, or ethanol, containing traces of
benzene. While ethenol, in it's natural form, is a source of
combustible fuel, it contains trace amounts of water making it less
efficient for burning than in it's denatured form. Introducing
Benzene during the distillation process drives out the water
contained in ethanol creating a very pure and potent fuel source -
denatured alcohol.
NOTE: Ethanol is the alcohol consumed in alcoholic beverages.
However, once denatured, ethanol becomes toxic and can cause
blindness or death if consumed.


You are confusing this with Methanol (wood alcohol). Denatured alcohol
(benzene dirtied ethanol) will not cause blindness. Death? Perhaps, if
enough is consumed. More than likely, though, cancer as well as a multitude
of other health problems.. Having worked with Benzenes for many years, I
think I can attest to this.

It's not my confusion; I cut and pasted that from a web site and didn't pay
attention to the 'note'. My comments were after the ------ separator.

Anyone who watches enough old prohibition period movies knows the problem with
"wood alcy"



snip

--
Strontium

"It's no surprise, to me. I am my own worst enemy. `Cause every
now, and then, I kick the livin' **** `outta me." - Lit

-
David Maynard stood up at show-n-tell, in , and
said:

Strontium wrote:
-
David Maynard stood up at show-n-tell, in ,
and said:


snip

Iodine tinctures, witch hazel, hydrogen peroxide, antibacterial
salves and lotions, or a whole lot of other stuff. Including other
alcohols. Using isopropanol as rubbing alcohol might be a regional
thing, because I'm used
to ethanol.

Denatured Alcohol vs. Isopropanol

Denatured Alcohol is ethyl alcohol, or ethanol, containing traces of
benzene. While ethenol, in it's natural form, is a source of
combustible fuel, it contains trace amounts of water making it less
efficient for burning than in it's denatured form. Introducing
Benzene during the distillation process drives out the water
contained in ethanol creating a very pure and potent fuel source -
denatured alcohol.
NOTE: Ethanol is the alcohol consumed in alcoholic beverages.
However, once denatured, ethanol becomes toxic and can cause
blindness or death if consumed.


You are confusing this with Methanol (wood alcohol). Denatured
alcohol (benzene dirtied ethanol) will not cause blindness. Death?
Perhaps, if enough is consumed. More than likely, though, cancer as
well as a multitude of other health problems.. Having worked with
Benzenes for many years, I think I can attest to this.

It's not my confusion; I cut and pasted that from a web site and
didn't pay attention to the 'note'. My comments were after the ------
separator.

Anyone who watches enough old prohibition period movies knows the
problem with "wood alcy"

Ahhhhhh! Didn't see your "Pasted from etc, etc..." disclaimer






snip


--
Strontium

"It's no surprise, to me. I am my own worst enemy. `Cause every
now, and then, I kick the livin' **** `outta me." - Lit

Intel and AMD do not demand that everyone use thermal
compound. They say to ill informed hobbyists to install
thermal compound because experience has demonstrated that
"degree C per watt" is too complex for some assemblers. For
those with some experience, any heatsink without the "degree C
per watt" parameter is suspect - at best.

But then, since thermal compound is so cheap (tens of times
less than what the overhyped Arctic Silver costs), then why
not provide thermal compound so that the bad CPU installation
does not cause permanent failure. Thermal compound is good
compensation for the ill informed computer system assembler.

In one Intel paper for engineers, the negative effects of
thermal compound are discussed. But that paper is beyond
scope of this discussion. A properly machine heatsink without
thermal compound will only cause single digit temperature
decrease on CPU ... IF heatsink is properly machined. If
thermal compound results in better temperature decreases, then
one must ask how improperly a heatsink was applied OR how poor
the heatsink really is.

If you dispute this, then the theoretical numbers can be
posted, obviously, OR examples provided from scientifically
controlled experiments. In the meantime, decades of
experience says that thermal compound results in only single
digit temperature reduction if the heatsink is properly
machined. This is science that was old even thirty years
ago. Why promote the hype of Arctic Silver, et al? They
already sell a product that is grossly profitable. Instead
promote the well proven science.

David Maynard wrote:
w_tom wrote:
A bare heatsink, properly machined, is more than sufficient
to cool a CPU. If thermal compound results in more than
defective. It probably was not sold with the all so necessary
"degree C per watt" parameter. Therefore they could not be
sued for failing to meet a specification - for selling a
defective product.

That spec is the first thing one seeks when buying a
heatsink. If the heatsink was so bad that it did not mate
properly to CPU - needed thermal compound - then heatsink was
not even machined and it would not provide a "degree C per
watt" spec. Thermal compound only reduces CPU temperature by
single digits IF heatsink is acceptable.

This must explain why not a single heatsink manufacturer provides
their heatsinks without thermal compound/pad and both Intel and
AMD emphatically state thermal compound must be applied and
provide instructions on how to do so.

A bare heatsink, properly machined, is more than sufficient
to cool a CPU. If thermal compound results in more than
single digit temperature decrease, then heatsink is
defective. It probably was not sold with the all so necessary
"degree C per watt" parameter. Therefore they could not be
sued for failing to meet a specification - for selling a
defective product.

This must explain why not a single heatsink manufacturer provides their
heatsinks without thermal compound/pad and both Intel and AMD emphatically
state
thermal compound must be applied and provide instructions on how to do so.

He's still correct. The best thermal interface is the flat, bare heatsink
against the core of the CPU. Unfortunately it's hard to account for all the
different sockets and other mounting mechanisms as well as poor handling by
the users, so paste is a lot safer.

On Sat, 06 Sep 2003 05:18:08 GMT, "Phrederik"
wrote:

A bare heatsink, properly machined, is more than sufficient
to cool a CPU. If thermal compound results in more than
single digit temperature decrease, then heatsink is
defective. It probably was not sold with the all so necessary
"degree C per watt" parameter. Therefore they could not be
sued for failing to meet a specification - for selling a
defective product.

This must explain why not a single heatsink manufacturer provides their
heatsinks without thermal compound/pad and both Intel and AMD emphatically
state
thermal compound must be applied and provide instructions on how to do so.

He's still correct. The best thermal interface is the flat, bare heatsink
against the core of the CPU. Unfortunately it's hard to account for all the
different sockets and other mounting mechanisms as well as poor handling by
the users, so paste is a lot safer.


Untrue, or at least not true in practice because there are no CPUs
THAT flat on top. The P4 spreader is nowhere near flat, nor is the
Athlon. The closest was the Coppermine P3 or Celeron, which unlike
the Athlon didn't have any laser-etching on the core, and even then
the final coating was often less than perfect.

Taking about theoretical best interface is meaningless when it is not
possible to achieve it with ANY off-the-shelf parts, without
refinishing them first. I'm fairly sure neither AMD or Intel will
warranty a CPU after it's planed down to perfection.

It may be true that two nearly-perfect parts (CPU & 'sink) will have
single-digit difference compared to using heatsink compound, but if
one is using one of the hi-spec 'sinks expected to start out somewhat
near flat, it's going to be providing effective enough cooling that
this single-digit difference may be a significant percentage of rise
over ambient temp. It is not madness to use thermal compound, many
components in electronic gear never expected to be seen by the eyes of
a consumer also use thermal compound for the benefit it provides.


Dave

w_tom wrote:
Intel and AMD do not demand that everyone use thermal
compound. They say to ill informed hobbyists to install

Following installation instructions is not "ill informed."

thermal compound because experience has demonstrated that
"degree C per watt" is too complex for some assemblers. For
those with some experience, any heatsink without the "degree C
per watt" parameter is suspect - at best.

But then, since thermal compound is so cheap (tens of times
less than what the overhyped Arctic Silver costs), then why
not provide thermal compound so that the bad CPU installation
does not cause permanent failure. Thermal compound is good
compensation for the ill informed computer system assembler.

And where are these 'good installers'? Not at Dell, or Compaq, or HP, or any
other manufacturer because they all use some kind of thermal interface material.

In one Intel paper for engineers, the negative effects of
thermal compound are discussed. But that paper is beyond
scope of this discussion.

Useless since you don't say which one it is and there are many papers discussing
the 'negative effects' of thermal compound, as well as thermal pads, graphite
sheet, and tape, and all the other interface materials. Nothing is 'perfect' and
they all have 'negative effects'. They also have different 'advantages'. That's
what engineering is about: selecting the best solution for the specifications
and conditions one has to work with in the real world.

A properly machine heatsink without
thermal compound will only cause single digit temperature
decrease on CPU ... IF heatsink is properly machined. If
thermal compound results in better temperature decreases, then
one must ask how improperly a heatsink was applied OR how poor
the heatsink really is.

Alpha PAL PAL8942M81. Expulsion0 .23 deg C/W, Induction
0.26 deg C/W. Comes with thermal grease and installation instructions spell out
to apply it. There is no 'exception' mentioned for 'if you're a good installer'.

Now you show me one of your readily available 'proper' CPU heatsinks that comes
without thermal compound and explicitly says you don't need it because it's so
wonderful.

If you dispute this, then the theoretical numbers can be
posted, obviously, OR examples provided from scientifically
controlled experiments.

Having already disputed it THIS was the time for you to post something
supporting your claims.

In the meantime, decades of
experience says that thermal compound results in only single
digit temperature reduction if the heatsink is properly
machined. This is science that was old even thirty years
ago.

What "decades of experience" shows is that virtually everyone uses some form of
thermal interface material with virtually every heatsink application involving
significant power, from CPUs to stereo power output transistors. Crack open your
PSU and you'll find thermal interface material between the power transistors and
their heatsinks. Pop the can off your P4 and you'll find thermal interface
material between it and the CPU die. The stuff is everywhere.

Why promote the hype of Arctic Silver, et al? They
already sell a product that is grossly profitable.

Where in the world you come up with the notion I 'promote' Arctic silver, or any
other product for that matter, is a complete mystery.

Instead
promote the well proven science.

There's a difference between theoretical and applied science.


David Maynard wrote:

w_tom wrote:

A bare heatsink, properly machined, is more than sufficient
to cool a CPU. If thermal compound results in more than
defective. It probably was not sold with the all so necessary
"degree C per watt" parameter. Therefore they could not be
sued for failing to meet a specification - for selling a
defective product.

That spec is the first thing one seeks when buying a
heatsink. If the heatsink was so bad that it did not mate
properly to CPU - needed thermal compound - then heatsink was
not even machined and it would not provide a "degree C per
watt" spec. Thermal compound only reduces CPU temperature by
single digits IF heatsink is acceptable.

This must explain why not a single heatsink manufacturer provides
their heatsinks without thermal compound/pad and both Intel and
AMD emphatically state thermal compound must be applied and
provide instructions on how to do so.

Phrederik wrote:
A bare heatsink, properly machined, is more than sufficient
to cool a CPU. If thermal compound results in more than
single digit temperature decrease, then heatsink is
defective. It probably was not sold with the all so necessary
"degree C per watt" parameter. Therefore they could not be
sued for failing to meet a specification - for selling a
defective product.


This must explain why not a single heatsink manufacturer provides their
heatsinks without thermal compound/pad and both Intel and AMD emphatically

state

thermal compound must be applied and provide instructions on how to do so.


He's still correct. The best thermal interface

Define "best."

I submit that being able to make it should be part of the criteria.

is the flat,

How flat? How smooth? (even though you didn't mention it.)

bare heatsink
against the core of the CPU.

How are you going to get it "against the core" of a P4?

Unfortunately it's hard to account for all the
different sockets and other mounting mechanisms as well as poor handling by
the users, so paste is a lot safer.

Then without it isn't "best."

"kony" wrote in message
...
On Sat, 06 Sep 2003 05:18:08 GMT, "Phrederik"
wrote:

A bare heatsink, properly machined, is more than sufficient
to cool a CPU. If thermal compound results in more than
single digit temperature decrease, then heatsink is
defective. It probably was not sold with the all so necessary
"degree C per watt" parameter. Therefore they could not be
sued for failing to meet a specification - for selling a
defective product.

This must explain why not a single heatsink manufacturer provides their
heatsinks without thermal compound/pad and both Intel and AMD
emphatically
state
thermal compound must be applied and provide instructions on how to do
so.

He's still correct. The best thermal interface is the flat, bare heatsink
against the core of the CPU. Unfortunately it's hard to account for all
the
different sockets and other mounting mechanisms as well as poor handling
by
the users, so paste is a lot safer.


Untrue, or at least not true in practice because there are no CPUs
THAT flat on top. The P4 spreader is nowhere near flat, nor is the
Athlon. The closest was the Coppermine P3 or Celeron, which unlike
the Athlon didn't have any laser-etching on the core, and even then
the final coating was often less than perfect.

Taking about theoretical best interface is meaningless when it is not
possible to achieve it with ANY off-the-shelf parts, without
refinishing them first. I'm fairly sure neither AMD or Intel will
warranty a CPU after it's planed down to perfection.

It may be true that two nearly-perfect parts (CPU & 'sink) will have
single-digit difference compared to using heatsink compound, but if
one is using one of the hi-spec 'sinks expected to start out somewhat
near flat, it's going to be providing effective enough cooling that
this single-digit difference may be a significant percentage of rise
over ambient temp. It is not madness to use thermal compound, many
components in electronic gear never expected to be seen by the eyes of
a consumer also use thermal compound for the benefit it provides.

Thanks for that. I've been watching this thread and also thought the same
thing about dies not being completely flat. What's the use of having a
totally flat HS base if the die is concave or convex?
--
~misfit~



---
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Checked by AVG anti-virus system (http://www.grisoft.com).
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~misfit~ wrote:
"kony" wrote in message
...

On Sat, 06 Sep 2003 05:18:08 GMT, "Phrederik"
wrote:


A bare heatsink, properly machined, is more than sufficient
to cool a CPU. If thermal compound results in more than
single digit temperature decrease, then heatsink is
defective. It probably was not sold with the all so necessary
"degree C per watt" parameter. Therefore they could not be
sued for failing to meet a specification - for selling a
defective product.

This must explain why not a single heatsink manufacturer provides their
heatsinks without thermal compound/pad and both Intel and AMD

emphatically

state

thermal compound must be applied and provide instructions on how to do

so.

He's still correct. The best thermal interface is the flat, bare heatsink
against the core of the CPU. Unfortunately it's hard to account for all

the

different sockets and other mounting mechanisms as well as poor handling

by

the users, so paste is a lot safer.


Untrue, or at least not true in practice because there are no CPUs
THAT flat on top. The P4 spreader is nowhere near flat, nor is the
Athlon. The closest was the Coppermine P3 or Celeron, which unlike
the Athlon didn't have any laser-etching on the core, and even then
the final coating was often less than perfect.

Taking about theoretical best interface is meaningless when it is not
possible to achieve it with ANY off-the-shelf parts, without
refinishing them first. I'm fairly sure neither AMD or Intel will
warranty a CPU after it's planed down to perfection.

It may be true that two nearly-perfect parts (CPU & 'sink) will have
single-digit difference compared to using heatsink compound, but if
one is using one of the hi-spec 'sinks expected to start out somewhat
near flat, it's going to be providing effective enough cooling that
this single-digit difference may be a significant percentage of rise
over ambient temp. It is not madness to use thermal compound, many
components in electronic gear never expected to be seen by the eyes of
a consumer also use thermal compound for the benefit it provides.


Thanks for that. I've been watching this thread and also thought the same
thing about dies not being completely flat. What's the use of having a
totally flat HS base if the die is concave or convex?
--
~misfit~

Actually, depending on what it is, a convex surface might be desired because it
might flex under load!

I'm not suggesting that's the case here. What I'm saying is that these things
are a heck of a lot more complex than the simple 'flat' kind of analysis folks
typically look at. Like, how much will the CPU package flex under the heatsink
clip pressure, as just one example.

Here's a pdf with, although not CPU related, some interesting information about
a particular component's heatsinking: http://www.ixys.com/t112901a.pdf

Note they intentionally convex the case to allow for deforming when it's bolted
down to the heatsink. Another interesting statement is "Therefore the flatness
of the heatsink across the module mounting area should be less than 25µm with a
roughness RZ less than 10µm which is a standard requirement for heatsinks."

Contact pressure is important so "it is recommended to use M5 screws secured by
a lock washer and flat washer torqued to between 2.7- 3.3 Nm (24 – 29 lb-inch).

And, of course, the ever present "The use of thermal grease is recommended to
ensure low case-to-sink thermal resistance." (and they list recommended types)


This link, http://www.thermaflo.com/interface.shtml , has a brief discussion of
thermal interface materials. Of particular note: "Unfortunately, no matter how
well prepared, when two typical electronic component surfaces are brought
together, less than one percent of their surfaces make physical contact. As much
as 99% of the surfaces are separated by a layer of interstitial air due to a
certain roughness caused by microscopic hills and valleys (surface finish) and
by macroscopic properties such as non-planarity in the form of a concave, convex
or twisted shape (flatness, twist, etc.)."

Its safe then, your not dead are you

or are you :0


On Fri, 5 Sep 2003 21:59:56 -0500, "Strontium"
wrote:


-
David Maynard stood up at show-n-tell, in , and
said:

Arthur Hagen wrote:
"AnthonyR" wrote in message
...

What do you mean the chemist didn't have alcohol?


Vin said that the chemists said they didn't have *isopropyl* alcohol
(isopropanol). Alcohol is at least a dozen different things, from
methanol
to glycerin.

(Also note that when he said chemist, he almost certainly meant what
we call
a drugstore here in the US.)


Do you not have rubbing alcohol in your house? here in the states
every
house has a bottle, its used to clean wounds and stuff.


We sure don't have a bottle. Is it mandatory?


What do you use for scraped knee's?


Iodine tinctures, witch hazel, hydrogen peroxide, antibacterial
salves and lotions, or a whole lot of other stuff. Including other
alcohols. Using isopropanol as rubbing alcohol might be a regional
thing, because I'm used
to ethanol.

Denatured Alcohol vs. Isopropanol

Denatured Alcohol is ethyl alcohol, or ethanol, containing traces of
benzene. While ethenol, in it's natural form, is a source of
combustible fuel, it contains trace amounts of water making it less
efficient for burning than in it's denatured form. Introducing
Benzene during the distillation process drives out the water
contained in ethanol creating a very pure and potent fuel source -
denatured alcohol.
NOTE: Ethanol is the alcohol consumed in alcoholic beverages.
However, once denatured, ethanol becomes toxic and can cause
blindness or death if consumed.

You are confusing this with Methanol (wood alcohol). Denatured alcohol
(benzene dirtied ethanol) will not cause blindness. Death? Perhaps, if
enough is consumed. More than likely, though, cancer as well as a multitude
of other health problems.. Having worked with Benzenes for many years, I
think I can attest to this.


snip