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Clyde stood up at show-n-tell, in
(e-mail address removed), and said:
Does anyone here have any evidence that 70% rubbing alcohol leaves any
residue on anything it cleans? If so, does that residue do anything to
harm heat transfer?
Nope. And, I wouldn't worry about it. However, I prefer the 'elbow
grease', with a lint free paper towel method.
I've been cleaning things with 70% for a number of decades. My doctor
father cleaned plenty of stuff with it, including wounded humans. I've
never seen any evidence of residue on anything properly cleaned with
it.
OK, I haven't been doing microscopic investigations on those surfaces,
but I'm also having a hard time believing that the contact between a
heatsink and a cpu is anywhere near that critical.
Then again, I'm having a hard time understanding why good solid metal
to metal contact isn't enough. That copper heatsink that came with my
P4 snaps in very hard. I can't imagine why the contact wouldn't be
more than enough. All that physics in HS and college would seem to
support this -- if I could remember that far back.
Assuming perfectly congruent surfaces, on the atomic level.... The whole
idea is to have the thermal resistance, between the two surfaces, as close
to zero as possible. Naturally, no two 'man-made' surfaces (made by
different people, in different parts of the plant, by different machines,
etc.....) are going to be matched, perfectly. If they were, you would be
paying $50,000 for a paired set of a heatsink and processor.
I also have a few decades of experience in other areas of life. For
example, a car engine has lots of metal to metal parts that get a heck
of a lot hotter than computers do. True, that have pretty good cooling
systems, but they aren't half as worried about the connection as this
group seems to be.
Maybe because the parts that are getting hot are not millions of small
transistors that will burn up....
Besides, why didn't Intel say anything about the connection in my P4
boxset? Their instructions just say how to put the chip in and then
snap that heatsink in on top of it. Not a word about cleaning or goop
or anything. Gee, don't they know what they are doing?
Hence....Usenet, community, experimentalism.
Well, some real evidence from someone other than the goop makers would
be real nice.
Personal experience has taught me that, although not necessary, a very thin
coat of thermal interface is good. Why? For me, I used to (still,
sometimes) overclock. Every bit of efficiency, in cooling, is very
important when I want to push past 'tested specifications'. Besides, I want
my parts running as cool as possible without extreme measures. Air cooling,
with a nice thin interface seems to work for me.
