[NTLUG:Discuss] PC Hardware Issue

[steve]

Robert Pearson wrote:
> On 12/21/06, Neil Aggarwal <neil at jammconsulting.com> wrote:
>> Robert:
>>
>> I have never heard that too much airflow could be a
>> problem.  Please explain.
>>
>> Thanks,
>>         Neil
> 
> I should have said that "too fast" airflow could be a problem.
> If you have a lot of airflow through a case, there is a chance that
> the air may not stay in contact with the heated surfaces long enough
> to remove the heat.

This is urban legend...there are no possible laws of physics that
support such a claim!  Read about Newton's law of cooling...no
mention there of speeds.  Rate of heat loss is proportional to the
square of the temperature difference...period.  The air in contact
with the surface warms up thus reducing the temperature differential
and because it's a square-law dramatically reducing the heat flow
out of the surface.  Replacing that warm air with cooler air helps
the heat flow.  The faster you replace it, the less heat it has
absorbed before it's replaced and therefore the more heat you can
suck out of the surface.

> A lesser problem this can cause is turbulence,
> which can create "hot spots".

...or lack of turbulence which can cause stagnation between
components or close-packed boards.  The aerodynamics of each
component and between boards and around cables is vastly complex
and predicting the location of hot spots as a function of air
speed is almost impossible.

Places where the air stagnates can be a problem - but generally, if
they get hot then convection will replace the air with cooler air
from elsewhere.  The question is whether that's enough - sometimes
it is, sometimes it isn't.

It's very hard to tell.

But we're getting way ahead of ourselves here.

Right now though we don't even know that this is an overheating
problem at all!

You need to do the test of getting a big household fan turned up
as fast as it'll go - and direct it right into the case (with the
lid off).  If the system still craps out with that much airflow
then you'll KNOW it's not to do with overheating.

Buying silver paste and messing around with moving boards and
repositioning cables is what you do AFTER you know you have a
heating problem.  But you are still in a position where it could
be:

1) Software issues with crappy ATI drivers.
2) Bad memory stick(s)
3) Bad graphics card
4) Bad motherboard
5) Insufficient power supply to cope with peak demand.
6) ...oh, yeah...and overheating.