Intel wants to slow down platform changes

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips Petter Settli <petsett@offline.no> wrote: Dean Kent wrote: use of Arctic Silver and such - which is not recommended). What's their problem with Arctic Silver?

I'm not precisely certain. I believe they are worried about
grease being extruded out by differential thermal expansion as
the CPU core heats and cools relative to the cold/hot heatsink.

Personally, I just don't buy it. I don't see why phase-change
material (that AMD recommends) is any less succeptible to
extrusion. And this extrusion can only make a very small
peripheral void that will likely be filled by bleed from
the grease. IMHO, AMD bought a saleman's pitch.

-- Robert author `cpuburn` http://users.ev1.net/~redelm

[George Macdonald]

On Tue, 01 Jul 2003 18:45:00 GMT, Robert Redelmeier
<redelm@ev1.net.invalid> wrote:
In comp.sys.ibm.pc.hardware.chips Petter Settli <petsett@offline.no> wrote: Dean Kent wrote: use of Arctic Silver and such - which is not recommended). What's their problem with Arctic Silver?I'm not precisely certain. I believe they are worried aboutgrease being extruded out by differential thermal expansion asthe CPU core heats and cools relative to the cold/hot heatsink.Personally, I just don't buy it. I don't see why phase-changematerial (that AMD recommends) is any less succeptible toextrusion. And this extrusion can only make a very smallperipheral void that will likely be filled by bleed fromthe grease. IMHO, AMD bought a saleman's pitch.

I've never used artic silver but every CPU I've removed which had had white
thermal "grease" applied had dried up - the white material (zinc oxide ?)
had turned into a thin cake. Also, I had a tube of the stuff lying in my
tool box for 15years or so and when I opened it a couple of years back
there was umm, significant separation of the liquid and the solid. This
was not Radio Shack brand - I bought it in an electronics parts store.

On the dried-up stuff, used on the CPUs, I could not see any sign of
seepage or staining of the ceramic around the CPU heat spreader and as a
former chemist I was interested in what happened to the oil/liquid
component. Did it evaporate? I didn't see any sign in the "cake" that it
had baked into a thicker binding agent. Certainly if you leave even high
boiling point petroleum type greases or oils sitting around they *do* dry
up - add heat cycling and they "disappear" more quickly - IIRC by
vaporization and oxidation.

Assuming the oil/grease component of traditional white heatsink "compound"
is silicone, I don't think it's susceptible to oxidation but it could
certainly evaporate... albeit extremely slowly. IIRC Artic Silver has a
"synthetic grease" as its carrier for the solid material which I'd think is
likely PAO (polyalphaolefin... as in Mobil1 products) and that's basically
a petroleum compound which is somewhat less susceptible to oxidation than
mineral-based oil.

So do you know: has anyone done any analysis of what actually happens to
the liquid carrier? As for the phase change material, I haven't looked
into exactly what they mean by phase change. Does it phase change
(temporarily) on every heat cycle, i.e. solid to liquid and back on cool
down or does it phase change permanently over the first few applications of
heat, from a paste to a hardish plastic?

Having said all that, I did a "clean-up" on my system's interior the other
day and I noted that the white heatsink compound on the graphics chip
heatsink was still quite "wet" and there was no sign of it turning into a
"cake". I'm puzzled by all this and the "science" seems hard to track down
- complicate by all the folklorish gossip that abounds on Websites.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

[SnowMan]

On Tue, 01 Jul 2003 18:45:00 GMT, Robert Redelmeier
<redelm@ev1.net.invalid> wrote:
In comp.sys.ibm.pc.hardware.chips Petter Settli <petsett@offline.no> wrote: Dean Kent wrote: use of Arctic Silver and such - which is not recommended). What's their problem with Arctic Silver?I'm not precisely certain. I believe they are worried aboutgrease being extruded out by differential thermal expansion asthe CPU core heats and cools relative to the cold/hot heatsink.Personally, I just don't buy it. I don't see why phase-changematerial (that AMD recommends) is any less succeptible toextrusion. And this extrusion can only make a very smallperipheral void that will likely be filled by bleed fromthe grease. IMHO, AMD bought a saleman's pitch.-- Robert author `cpuburn` http://users.ev1.net/~redelm


And for the Opteron AMD says, use paste not pads.

[Neo]

Yes, a phase change material liquifies when heated and is nearly solid when
cold.

"George Macdonald" <fammacd=!SPAM^nothanks@tellurian.com> wrote in message
news:3f0216ea.47377028@news.tellurian.com... On Tue, 01 Jul 2003 18:45:00 GMT, Robert Redelmeier <redelm@ev1.net.invalid> wrote:In comp.sys.ibm.pc.hardware.chips Petter Settli <petsett@offline.no>
wrote: Dean Kent wrote:> use of Arctic Silver and such - which is not recommended). What's their problem with Arctic Silver?I'm not precisely certain. I believe they are worried aboutgrease being extruded out by differential thermal expansion asthe CPU core heats and cools relative to the cold/hot heatsink.Personally, I just don't buy it. I don't see why phase-changematerial (that AMD recommends) is any less succeptible toextrusion. And this extrusion can only make a very smallperipheral void that will likely be filled by bleed fromthe grease. IMHO, AMD bought a saleman's pitch. I've never used artic silver but every CPU I've removed which had had
white thermal "grease" applied had dried up - the white material (zinc oxide ?) had turned into a thin cake. Also, I had a tube of the stuff lying in my tool box for 15years or so and when I opened it a couple of years back there was umm, significant separation of the liquid and the solid. This was not Radio Shack brand - I bought it in an electronics parts store. On the dried-up stuff, used on the CPUs, I could not see any sign of seepage or staining of the ceramic around the CPU heat spreader and as a former chemist I was interested in what happened to the oil/liquid component. Did it evaporate? I didn't see any sign in the "cake" that it had baked into a thicker binding agent. Certainly if you leave even high boiling point petroleum type greases or oils sitting around they *do* dry up - add heat cycling and they "disappear" more quickly - IIRC by vaporization and oxidation. Assuming the oil/grease component of traditional white heatsink "compound" is silicone, I don't think it's susceptible to oxidation but it could certainly evaporate... albeit extremely slowly. IIRC Artic Silver has a "synthetic grease" as its carrier for the solid material which I'd think
is likely PAO (polyalphaolefin... as in Mobil1 products) and that's basically a petroleum compound which is somewhat less susceptible to oxidation than mineral-based oil. So do you know: has anyone done any analysis of what actually happens to the liquid carrier? As for the phase change material, I haven't looked into exactly what they mean by phase change. Does it phase change (temporarily) on every heat cycle, i.e. solid to liquid and back on cool down or does it phase change permanently over the first few applications
of heat, from a paste to a hardish plastic? Having said all that, I did a "clean-up" on my system's interior the other day and I noted that the white heatsink compound on the graphics chip heatsink was still quite "wet" and there was no sign of it turning into a "cake". I'm puzzled by all this and the "science" seems hard to track
down - complicate by all the folklorish gossip that abounds on Websites. Rgds, George Macdonald "Just because they're paranoid doesn't mean you're not psychotic" - Who,
me??

[Robert Redelmeier]

My newserver missed George's post.

In comp.sys.ibm.pc.hardware.chips Neo <genuineintel@comcast.net> wrote: Yes, a phase change material liquifies when heated and is nearly solid when cold. "George Macdonald" <fammacd=!SPAM^nothanks@tellurian.com> wrote in message thermal "grease" applied had dried up - the white material (zinc oxide ?) had turned into a thin cake. Also, I had a tube of the stuff lying in my

I wouldn't be worried so long as the cake was still a bit
moist. Not dry and powdery. The carrier fluid (silicone,
petroleum, poly alphaolefins or polyester) in thermal grease
doesn't have good conductivity except compared to air.
The solids do most of the work.

All greases bleed, and thermal grease isn't even compounded
to be really stable. I'd fully expect harmless separation
over time. Some may be good in a spring-pressure joint like
HSF onto CPUs. Heat and vibration will cause the grease to
extrude & bleed, giving a thinner, higher conductivity layer.
On the dried-up stuff, used on the CPUs, I could not see any sign of seepage or staining of the ceramic around the CPU heat spreader and as a former chemist I was interested in what happened to the oil/liquid

I suspect most of the excess carrier fluid bled onto the
anodized aluminum of the heatsink. From there or the ceramic
it could easily evaporate because the HSF air discharging
from the fins will educt air from under the heatsink.
likely PAO (polyalphaolefin... as in Mobil1 products) and that's basically a petroleum compound which is somewhat less susceptible to oxidation than mineral-based oil.

At these cold temps, I'm not sure PAO is more oxidation
resistant than petroleum (with the sulfur in it). In any case,
I don't think either oxidizes.
day and I noted that the white heatsink compound on the graphics chip heatsink was still quite "wet" and there was no sign of it turning into a "cake". I'm puzzled by all this and the "science" seems hard to track

Less pressure, vibration or airflow (omnidirectional pin HS).

-- Robert author `cpuburn` http://users.ev1.net/~redelm

[George Macdonald]

On Fri, 04 Jul 2003 01:45:14 GMT, "Neo" <genuineintel@comcast.net> wrote:
Yes, a phase change material liquifies when heated and is nearly solid whencold.

Well that's *one* type of phase change - a thermoplastic one... i.e.
reversible. I just wondered if the stuff AMD uses/recommends worked like
that... or if it might be thermosetting. I've never had to take the
heatsink off an installed CPU to see what the stuff looks like after it's
been in "action".
"George Macdonald" <fammacd=!SPAM^nothanks@tellurian.com> wrote in messagenews:3f0216ea.47377028@news.tellurian.com... On Tue, 01 Jul 2003 18:45:00 GMT, Robert Redelmeier <redelm@ev1.net.invalid> wrote:In comp.sys.ibm.pc.hardware.chips Petter Settli <petsett@offline.no>wrote:> Dean Kent wrote:>> use of Arctic Silver and such - which is not recommended).>> What's their problem with Arctic Silver?I'm not precisely certain. I believe they are worried aboutgrease being extruded out by differential thermal expansion asthe CPU core heats and cools relative to the cold/hot heatsink.Personally, I just don't buy it. I don't see why phase-changematerial (that AMD recommends) is any less succeptible toextrusion. And this extrusion can only make a very smallperipheral void that will likely be filled by bleed fromthe grease. IMHO, AMD bought a saleman's pitch. I've never used artic silver but every CPU I've removed which had hadwhite thermal "grease" applied had dried up - the white material (zinc oxide ?) had turned into a thin cake. Also, I had a tube of the stuff lying in my tool box for 15years or so and when I opened it a couple of years back there was umm, significant separation of the liquid and the solid. This was not Radio Shack brand - I bought it in an electronics parts store. On the dried-up stuff, used on the CPUs, I could not see any sign of seepage or staining of the ceramic around the CPU heat spreader and as a former chemist I was interested in what happened to the oil/liquid component. Did it evaporate? I didn't see any sign in the "cake" that it had baked into a thicker binding agent. Certainly if you leave even high boiling point petroleum type greases or oils sitting around they *do* dry up - add heat cycling and they "disappear" more quickly - IIRC by vaporization and oxidation. Assuming the oil/grease component of traditional white heatsink "compound" is silicone, I don't think it's susceptible to oxidation but it could certainly evaporate... albeit extremely slowly. IIRC Artic Silver has a "synthetic grease" as its carrier for the solid material which I'd thinkis likely PAO (polyalphaolefin... as in Mobil1 products) and that's basically a petroleum compound which is somewhat less susceptible to oxidation than mineral-based oil. So do you know: has anyone done any analysis of what actually happens to the liquid carrier? As for the phase change material, I haven't looked into exactly what they mean by phase change. Does it phase change (temporarily) on every heat cycle, i.e. solid to liquid and back on cool down or does it phase change permanently over the first few applicationsof heat, from a paste to a hardish plastic? Having said all that, I did a "clean-up" on my system's interior the other day and I noted that the white heatsink compound on the graphics chip heatsink was still quite "wet" and there was no sign of it turning into a "cake". I'm puzzled by all this and the "science" seems hard to trackdown - complicate by all the folklorish gossip that abounds on Websites. Rgds, George Macdonald "Just because they're paranoid doesn't mean you're not psychotic" - Who,me??

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??