I have always used thick business card stock as a trowel to spread the
AS on CPU heat spreaders.
A very thin smooth layer of AS that you can see through is all that's
needed. Too thick a layer actually impedes heat transfer. The trick and
where the learning curve comes is applying the thin consistent layer on
the spreader with no air bubbles or bare spots.
When building PC's I will install the heat sink and then uninstall it to
make sure there is complete consistent coverage.
Reminds me of my overclocking days when we used to lap grind CPU heat
spreaders and heat sinks to get them a flat as possible to maximize
contact area.
On 2/6/2015 12:13 AM, Roger (K8RI) wrote:
I've been using Arctic Silver since it came out. With over 20 builds
under my belt, I've never had a problem with shorts. There is a
learning curve on just how much to use with out "run over". You put a
small "pile" in the center of the object to be cooled. Using a mild
pressure (learning curve here too) you press down on the cooler, or
heat spreader with a small rotating (oscillating) motion. Yes, it
wastes a bit of expensive compound, but you could practice with some
of the cheaper stuff. Just remember, they may not spread exactly the
same. BUT BE NEAT! The current 5 builds run 4 GHz to 5 GHz. That 5
GHz chip (4.7 stock), dumps an easy 240 watts of heat through a
surface area just under 1.5 X 1.5" an inch square (3.8 X 3.8 cm sq)
or 14.44 sq cm. Just think of the dimensions involved for circuits
running 4 to 5 GHz.
Some of those old chips ran close to 90 C. Today, even over clockers
try to maintain close to 40 C, but not always.
BTW that 5 GHz chip uses a closed circuit water cooling system with
push/pull fans on the radiator.
All heat sink compounds I've used since the little, ultra noisy 90 mm
fans with the heat spreader right on top of the exposed Silicon die,
cure and gain conductivity. I think some support chip coolers are
positioned where you will break the bond while working in there.
We can hope the SS power modules for ham amps will mature as fast as
the computer technology has.
When I did my first build, all choices were made by jumper position.
Now, it's rare not to be able to do the few remaining manual choices,
usually reserved for the over clockers in software. For most of us
mortals, the selections are automated. Install the OS, then before
anything else, run the motherboard support and driver disk. Then the
driver(s) for the video card (if it has one.)
BTW I had an 8 oz tube of the white silicone thermal grease. Cost me a
buck! <:-))
73
Roger (K8RI)
--
R. Kevin Stover
AC0H
ARRL
FISTS #11993
SKCC #215
NAQCC #3441
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