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A new heatsink compound (thermal grease)

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  • Overclocking
  • Heatsinks
Last response: in Overclocking
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September 26, 2004 3:51:52 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Hello All

Henkel Loctite have released a new heatsink compound which comes in the form
of a bar of material, deployed rather like a lip-stick.

You rub it on the heatsink/component interface and it applies an appropriate
layer of solid material. under high clamping pressures, the solid undergoes
a change to a liquid at 60 deg C (approx. 150 deg F) and is forced into all
the tiny gaps (present due to imperfections, machining tolerances etc.).

The thermal conductivity is 20% lower than the usual thermal grease - it
says it's 0.03 degC/W at 20psi clamping pressure, dropping to 0.02 degC/W at
100psi - and gives 100% surface wetting with easy application, it says.

My Prescott, o/c from 3 to 3.3 GHz, is running at stock voltages with the
stock Intel heastink. CPU temps reported by MBM5 (Abit AI7) are 60-62 deg C.
I plan to re-mount the heatsink having applied some of this thermstrate, and
I'll let you know if I see a drop in temperature. The current heatsink
compound is the usual white alumina-loaded stuff.

Here's some info on thermstrate:
http://makeashorterlink.com/?D4F321069

Does anybody know what the thermal conductivity is that's quoted for the
silver-loaded materials?

Cheers

RMC, England

More about : heatsink compound thermal grease

September 26, 2004 3:51:53 AM

Archived from groups: alt.comp.hardware.overclocking (More info?)

On Sat, 25 Sep 2004 23:51:52 +0100, "RMC" <RMC@home.com> wrote:

>Hello All
>
>Henkel Loctite have released a new heatsink compound which comes in the form
>of a bar of material, deployed rather like a lip-stick.
>

Seems this kind of stuff has been around for awhile, they sell it to
system builders.

Not very good.

I'd use radio shack white stuff instead.
Anonymous
a b K Overclocking
September 27, 2004 10:19:16 PM

Archived from groups: alt.comp.hardware.overclocking (More info?)

Sounds like it is more aimed at integrators/production:
o The critical factor there is skill & cycle time

GM can turn out perfect all plastic cars - but the cycle time per panel
is still that bit more than steel, and so the economics aren't there yet.

The difference between (modern) TIM, silver-loaded & plain heatsink
compound is relatively small. Not using too much is as big a factor in
its performance as the particular material chosen - it's 2-3oC at most.

So give it a try, but don't expect something particularly radical:
o Heatsink & CPU die/spreader are two metal surfaces with microscopic voids
o Voids can be filled with air, or with some form of heatsink compound
o Heatsink compound's heat transfer is significantly inferior to metal
o However, heatsink compound's heat transfer is significantly better than air

So it doesn't make your heatsink bigger. A better compound may minimise small
localised hotspots on the die/spreader, and may help some overclocking situations.

The heatspreader itself can be improved - although not by end-users:
o Heatspreader undersides are a plate & glob of glue to the chip die
---- thus the heatspreader presents a single flat plate to the die
---- thus the glue/thermal-compound is thicker than it need be
o Alternative heatspreader undersides are a plate of 4 (2x2) or 9 (3x3) posts
---- the posts contact the die more closely than a normal heatspreader
---- so less thermal compound exists in the interface, better transfer, fewer hotspots

Physical mockups & flotherm (3D FEA) have been used to prove the concept,
but I think the chip makers are still using the older type - "it's cheap, why fix it".

Playing around with a duct from the CPU heatsink outlet to a nearby exhaust fan
can have a bigger impact on your temperatures. Foamex (sign makers) is a foamed
PVC between a thin skin of PVC - a thermoplastic to easily hand moulded into ducts.
--
Dorothy Bradbury
www.stores.ebay.co.uk/panaflofan for quiet Panaflo fans & other items
www.dorothybradbury.co.uk (free delivery)
!