Archived from groups: comp.sys.laptops (
More info?)
Andrew wrote:
> Quaoar <quaoar@tenthplanet.net> wrote:
>> Heat pipes started in a big way with the P4 2+Ghz CPUs due to heat
>> generation that mimics industrial furnaces. The traditional fan/heat
>> sink would of necessity be too large to fit in the case. Look at the
>> 3+Ghz P4 laptops, if you can find one any more, with the heat pipe
>> air exchanger arranged across the entire rear panel.
>
> But the Pentium M (part of Centrino) CPU doesn't get that hot so
> probably doesn't use heat pipes, right? And the OP was using a
> Pentium M (just to get back to the original post).
>
> Andrew
Heat pipes are far more efficient for CPU cooling than is the
traditional fan/heatsink. Not only are they more efficient, but the
heap pipe attachment to the CPU is small and compact and with more
efficient CPUs the heat exchanger is also small and can be placed in any
"leftover" space. The radial fans are also compact and fairly quiet.
Designers now use heat pipes in almost every laptop since it gives them
more design flexibility in thinner cases. The heat pipe can function
without or with minimal fan for a small heat load on lower speed CPUs.
That won't work on the P4 since it is generating significant heat even
at idle. Back to the Centrino/Pentium M, yes it is likely that it has a
heat pipe of one or two tubes.
Because of the way the the heat pipe air exchanger is designed with low
clearance fins surrounding the pipes to maximize heat rejection, the
exchanger invites plugging with fibers over time. On the P4 this can
result in a sudden thermal shutdown since the fan is always running and
the user becomes accustomed to the noise and doesn't notice that the fan
is running faster over time. The OPs observation is consistent with a
heat exchanger that is becoming obstructed, although there are other
reasons like more intensive use that can make the fan run harder, or
higher ambient temperature as summer approaches that raises the
temperature vs. load curve making the fan run harder.
The routine maintenance solution is simple: blow back through the
exchanger from the exit with computer dust cleaner or compressed air.
The fan should be restrained with a paper clip to prevent overspeed
damage. This will remove minor accumulations through the fan inlet.
More serious plugging as a mat resembling felt can be fixed only by
opening the case and physically removing the material. Sony Vaio P4
laptops are notorious for requiring physical removal since the fan
inlets do not have a screen but only simple slots in the case that pass
everything in the air. Other vendors install a metal screen that is
effective in removing the bulk of the fibers before they get a chance to
plug the exhanger.
I might have answered your question somewhere in this ...
Q
/www.bizave.com
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