Thanks for info that silver grease is electrically conductive and your
opinion of its use (or not <G>). I agree that silver grease being
electrically conductive is important to know. The manufacturers even agree
with you and print it boldly on the package as a caution.

Fact: Silver grease is 10 (4.8 Vs 55 Btu/hr) times more conductive thermally
than zinc. IMO, a factor of ten is more than "slightly more". This greater
conductivity results in real world temperature drops of 10°+F at the CPU.
This amount may not seem significant at first, but let me walk you down the
path of real world.

The reason it is significant is that it can mean the difference of a stable
system verses a
non-stable system since in a "typical" system the airflow is such that if
the ambient is above 85°F, the inside of the box is 100°+F. This is based on
numerous real world tests. (This is typical not inclusive) Using this data,
not opinion, on a K6-III system using an approved (not oversized) CPU cooler
by Cool Master, the CPU temperature would be 61.9°C and the maximum CPU
operating temperature is 65°C. In this case <G>, the CPU would only be 3.1°C
(5.6°F) below it maximum temperature. Now if the ambient air is over 90°F,
which is common here in the south, the CPU is above maximum operating
temperature. Add a years worth of dust bunnies or a non-approved
(undersized) CPU cooler which I have seen very common in systems built by
other than me, and the CPU is over maximum temperature at even 85°F room
temperature. Also from real world test, the closer the CPU is to maximum
operating temperature, the less stable it is.

So I would agree with you that care must be taken not to smear the grease
anywhere except on the top of the CPU which is a relatively easy task.
However, I disagree with you WRT that I feel it is significant and the added
risk due to conductivity can easily be avoided through common sense and a
little bit of care. Furthermore, conductivity is relative, and although zinc
grease is on the low end, when I used it, I also treated it as being
conductive and took the same care to not get it anywhere except on the top
of the CPU.

Lastly, WRT the cost, IMO $15 for a tube of grease that can be used on over
15 systems, i.e. less than $1 per system, is not a significant cost when
considering that the total cost of materials (components) is over $500 for
the system.

Thanks for the discussion.

Daniel Wysocki
Twin*.*Star Computers
770-498-2582 / 800-816-0663
[log in to unmask]
Fast - Reliable - Wallet Friendly


-----Original Message-----
From: [log in to unmask] <[log in to unmask]>
>  One important point you fail to mention is that silver heatsink paste is
>electrically CONDUCTIVE, and will short things out if you get it on
ANYTHING
>but the CPU to heatsink interface. The zinc oxide grease is NOT
electrically
>conductive (but highly thermally conductive), so you don't have this
problem.
>  The silver grease is slightly more thermally conductive, but the risk of
>damage through smearing to unwanted spots makes this a VERY risky
suggestion.
>If you do get it between pins of the CPU, or even more so, the cache chips,
>it is nearly impossible to completely clean out (the pins on cache chips
are
>extremely close together). That's assuming you catch this before you apply
>power, and possibly fry something.
>  I have used the silver grease on a couple of occasions, and it made no
>measurable difference in the temperature of the CPU Vs the zinc oxide
grease,
>both properly applied. Therefore, I would be hesitant to recommend it, (not
>to mention the MUCH higher cost of the silver paste).
>
>Just my .02 worth,
>Peter Hogan
>[log in to unmask]
>

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