Rob wrote:
On 18/05/2011 11:23, Skybuck Flying wrote:
It might seem "we computer people" are getting fooled/scammed by
specifications ((unrealistic)CFM).

I sure hope that's not the case because then all of your calculations are
wrong...

and with "your" I mean everybody that used CFM.

You might want to read up on this stuff:

http://en.wikipedia.org/wiki/Actual_...eet_per_minute

"real cfm"

For now after a quick glance I am thinking my atmosperic calculations
might
actually be closer to the truth

Time will tell ! =D

Bye,
Skybuck.

wrote in message
...
Skybuck Flying wrote:
Alternative thread in case original thread don't produce no results or
some miss it ! =D

Important topic ! =D

Hello,

I'm curious if it's possible to build a powerfull PC/iCore/GPU/Cuda PC
without getting into heat problems !

For example CPU has about 30 TDP (which is close to watts, otherwise
find
watts listing) and GPU could have as much as 200 to 300 TDP (watts)
(top
model for maximum bandwidth).

Additional watts for memory( 20 watt ? just guessing )
/motherboard (10
watt ?)/4 harddisk (60 watt*4=240)

Let's say 800 watts.

How much CFM would be needed to get rid of all that heat ?!?

A CFM heat (PC) calculator would be most handy... maybe somebody can
make/program it.

What would be good formula's to use ?!?

Bye,
Skybuck =D


CFM = 3.16 * Watts / Delta_T_degrees_F

Say room temperature is 72F, case air temperature target is 90F,
computer watts is 200 watts.

CFM = 3.16 * 200 / (90 - 72) = 35CFM

You can get around three times that airflow rating from a fan like this,
but you don't want to be sitting next to this. The fan draws
12V @ 1A and should not be connected to the motherboard header.
You can run this off a Molex drive connector.

http://www.circuittest.com/cfa121203...l-bearing.html


DDR3 memory DIMMs are around 2W. Hard drives are less than 12W. Your
800W number needs to be reworked.

Paul

Paul's calculation is correct. He knows what he is talking about.

That's the only equation I know of, off hand. I'm not a thermal engineer,
and cribbed that off a web page that detailed how to put a computer
into an enclosure, and ensure it got enough cooling air. I expect
there is some room for using pressure curves for the fan, but I
don't know the first thing about that. I had an engineer at work,
who used to do that part for us. When you work in a big company,
you're generally "stuck in a silo".

Paul