Archived from groups: alt.comp.hardware.homebuilt (
More info?)
Jerry Lewis wrote:
> What do you think about using this type of device to keep your notebook cooler
>
>
http://www.hardwarecooling.com/product_info.php/cPath/33/products_id/226
I've never tried one as my notebook doesn't really need it.
But if you're referring to the 'industrial' device I mentioned, the reason
for it's configuration was because of the environment it was going into.
Fans were not allowed so that precludes the cooler in the link. Plus, it
would lower the battery run time.
And last, it was a pen tablet computer intended to be carried in use and
strapping fans onto it would be mechanically, as well as operationally,
impractical.
> David Maynard <dNOTmayn@ev1.net> wrote in message news:<10fool7ov68v5f1@corp.supernews.com>...
>
>>Dorothy Bradbury wrote:
>>
>>
>>>o Copper heatsinks with thin skived fins
>>>---- high surface area in a small (low height) package
>>>o Heatpipe technology
>>>---- so actively moving heat from a CPU hot-plate to the heatsink
>>>
>>>Whilst it may appear remarkable re cooling, it's a combination of 2 things:
>>>o Running the chips hotter than most desktops
>>>---- and quite severe clock throttling on the P4 laptops
>>>o Using diagonal fans rather than conventional axial/radial fans
>>>---- these mix a combination of axial (cfm) & radial (pressure) properties
>>>---- load a laptop CPU, and the noise can be really quite surprising
>>>-------- narrow-skived-fin are great for area, terrible for airflow noise
>>>
>>>Centrino, P-M, is a different animal and more like a Mobile Athlon:
>>>o It offers performance comparable to the desktop P4s
>>>o At considerably lesser thermal output than desktop P4s
>>>
>>>The Mobile Athlon is a great chip and should have killed off the laptop
>>>use of P4-Celeron's but hasn't mainly thro tied-supply contracts I suspect.
>>>
>>>The P-M is a true laptop processor, the others often plain Skt 478 desktop
>>>processors which has a heat penalty. Celeron aren't so bad heat wise, but
>>>the top-end P4 processors are extremely inefficient compared to a P-M.
>>>
>>>1U, a rack-mount ~44mm height package uses a similar cooling system to
>>>laptops - low-height skived-fin copper heatsink with local fan or remote fans.
>>>o Local fan involves a lower height heatsink & slim 10mm axial fan
>>>o Remote fan involves a tall heatsink & remote twin 40x28mm axial fans
>>>
>>>Laptops do run hot with a higher operating temperature design than desktops.
>>>Many think that means they can operate in higher ambient temperatures, this is
>>>not actually the case - they tend to require ambient to be <=35oC whereas a
>>>desktop will operate in 40oC or even higher (subject to HD mainly). Hence a
>>>laptop designed for desert environment as well as having a daylight viewable
>>>TFT also has quite extensive thermal system beyond present laptops, and tends
>>>to use P-M which is an architecture Intel needs in the P4 re thermal efficiency.
>>>
>>>As for laptop, that term has been dropped by manufacturers since most will
>>>overheat if used on your lap due to 1) thermal output (your legs are near 37oC
>>>whereas ambient air is typically 15-25oc) or 2) blocking air intake vents.
>>>
>>>Surprisingly, few laptops heatsink-to-the-case via a heatpipe.
>>
>>The reason for that is HOT CASE. As you've pointed out, laptops often run
>>inherently warmer and the case at 50-60C, even if only at the initial
>>contact point, can be a real human touch problem.
>>
>>That's not 'theoretical'. I've seen an industrial 'laptop' (sealed case was
>>a requirement) with precisely that problem.
>>
>>
>>>Some do - and it wouldn't be hard to change many laptop base-covers to an
>>>aluminium design which made thermal contact with key component areas. Instead
>>>most have increased density inside the laptop and used various vents - such as on
>>>the rear for the graphics card passive heatsink, or in front of the memory on the
>>>base, and various slots in the EMF shields inside. A lot of heat is dumped through
>>>the keyboard on most laptop designs - it's less thermally-sensitive & large-area.
>>>
>>>Dissappointing to see no Mobile Athlon laptops from Dell and such like.
>>>For low noise/low heat the Mobile Athlon will work on desktop boards too,
>>>something the P-M will not do - emphasising how bad the Prescott is thermally.
>>
>>One aspect that no one has mentioned yet is different 'operating'
>>presumptions. Laptop manufacturers often set the 'normal' operating
>>criteria with 'typical usage' as not 100% speed all the time and so the
>>thermal system cannot handle continuous 100% loads at the rated ambient (or
>>rather, that's why the revised 'presumption'). Under normal 'burst' usage
>>it's fine but under sustained load they throttle back processor speed,
>>based on temperature (or an estimate of how much power is 'needed' to run
>>what's operative), to limit the heat output.
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