[rescue] This Just In: HP to buy Compaq

[Steve Pacenka]

At Sat, 15 Sep 2001 22:59:14 -0400 Greg A. Woods <woods at weird.com> wrote:

>[ On , September 15, 2001 at 19:16:48 (-0700), Gregory Leblanc wrote: ]
>> Subject: Re: [rescue] This Just In: HP to buy Compaq
>>
>> On Sat, 2001-09-15 at 17:46, Greg A. Woods wrote:
>> [snip]
>> > Intel's own specifications (if I understand them correctly) you need at
>> > least a 0.5" heat sink and a small fan providing 400 LFM airflow under
>> 
>> What on earth is an LFM?
>
>"Linear Feet Per Minute"
>
>I really don't quite understand how to apply that to air flow though,
>unless perhaps they mean "at the depth of the heat sink"....

Right, that's a velocity of air over the heat sink, implicitly at some 
standard distance from the heat sink surface and implicitly averaged over the 
air-contact surface area of the heat sink.  You remove heat from the heat sink 
by flowing cool air over its surfaces.  If the air is still, a much larger 
heat sink and much cooler incoming air are needed to remove a given chip's 
heat.

CFM is a chassis-scale scale measure of cooling, and links to LFM via 
establishing the temperature of air that arrives at the heat sink.

>No doubt there's some internal document at Intel detailing how they
>measure heat output and apply cooling principles, but their public
>manuals are surprisingly sparse (as opposed to say those from Seagate
>which are surprisingly detailed and specific).

Professional society and US military standards would be good references.

-- SP