Archived from groups: alt.comp.hardware.pc-homebuilt (
More info?)
First, almost all heat to heatsink transfers at center of
CPU. Heat transfers from outside edge of CPU into heatsink
are irrelevant and considered zero.
Second, to be effective, most of heatsink contacts CPU
directly resulting in better thermal conductivity. Thermal
resistance increases with change of media. If too much Arctic
Silver (which is no different from the other much less
expensive thermal compounds) is applied, then little CPU
direct to heatsink contact exists. Thermal conductivity from
CPU through Arctic Silver, and then into heatsink is
decreased. This increase in thermal resistance is
undesirable. Best to minimize use of thermal compound.
Third, too much thermal compound means thermal compound
oozing out. This contamination is bad for CPU electrical
operation and a source of intermittent failures.
Four, a properly machined heatsink needs no thermal
compound. Thermal compound on properly machined heatsinks
typically reduces CPU temperature by single digit degrees - an
insignificant number. Pay special notice to those who post
the numbers rather than just hype speculative myths. The job
of thermal compound is to fill microscopic holes in the CPU to
heatsink interface. Very little thermal compound does this.
Fifth, if thermal compound is properly applied, then it
remains in the inner one half of CPU to heatsink interface -
where the heat transfer occurs.
Six, thermal compound does two things - it fill microscopic
holes to marginally increase thermal conductivity AND it may
compensate for the many computer assemblers who never bother
to first learn numbers. A defectively machined heatsink
assembly does not provide the all so important degree C per
watt number. IOW cheap heatsink is being marketed to computer
assemblers who don't learn the numbers AND then hype Arctic
Silver; also without numbers.
Thermal compound should only fill microscopic holes at
center of the CPU to heatsink interface. Little is required.
This made obvious from the more responsible heatsink
manufacturers (who also provide numbers with their app notes)
and from industry technical papers (among the many).
Never trust what Arctic Silver says without independent
confirmation. They routinely hype half truths to sell more
product at many times excessive price. They routinely avoid
numbers for profitable reasons. With numbers, then one might
learn Arctic Silver is no better and grossly overpriced. They
market is to those who just know, never bother to learn
numbers, and don't even know where the heat transfer from CPU
to heatsink occurs.
Some defective heatsink manufacturers increase profits by
using thermal tape. Just another symptom of defective
heatsinks made for computer assemblers who never demand
numbers.
Al Smith wrote:
> Yes, Arctic Silver is wrong. No, I haven't used their product, but
> if you put a glob of paste in the middle of the surface and just
> press the heatsink onto the processor, you will never get an equal
> coverage. Even if it squeezes out on the corners all around and
> makes a mess, it will be thicker in the center. More probably, it
> will not make it to the edges all around, resulting in only
> partial contact of the heatsink with the CPU.