[CUBE] Giga Upgrade/Thermal paste/Sleep

[Bumala, Robert W]

  As an electrical engineer who designs systems for space, I have to design boards for conductive cooling, and one thing I can tell you, thermal paste will greatly improve the thermal conductivity between two plates.  If you take two plates, no matter how carefully you machine them for smoothness, you'd find that they are very rough microscopically, in fact they would only touch in a few places across the entire plate.  The only place that the two plates make good conduction is directly under the screws holding them together.
  The temperature of an electronic part is equal to the power dissipated by the device times the thermal resistance of the cooling interface.  The thermal resistance is inversely proportional  to the area of the interface.  In other words, by not using thermal paste, you reduce the thermal interface to just the area around the screw holes, increase the thermal resistance, and make the CPU run hotter.  
  This would however not make the cooling fins any hotter, just the CPU.    
A good book on this subject is "Thermal Computations For Electronic Equipment" by Gordon N Ellison
Bob.

----------------------

Robert W. Bumala
Circuit Design Engineer Staff
Lockheed Martin Advanced Technology Center

Lockheed Martin Space Systems Company
Org. L9-42  Bld. 255
3251 Hanover Street
Palo Alto, CA 94304-1191

Phone: (650) 354-5918
Fax:      (650) 424-3333
EMail: Robert.W.Bumala at lmco.com 

 -----Original Message-----
From: 	Cube List [mailto:Cube at lists.themacintoshguy.com]  On Behalf Of Laurie A Duncan
Sent:	Wednesday, November 26, 2003 8:02 PM
To:	Cube List
Subject:	Re: [CUBE] Giga Upgrade/Thermal paste/Sleep

On 11/26/03 10:34 PM,"Anthony Kulesa" <tmandesign at mac.com> typed the
following:

> A comment from "Cube Guru" about thermal paste can be found here:
> 
> http://www.cubeowner.com/forums//index.php?
> s=ec921d147e84520a154e1df8daa8455b&showtopic=4179&st=40

I believe the specific post you are referring to is by Straker, and it can
be found here:

<http://www.cubeowner.com/forums//index.php?showtopic=4179&view=findpost&p=2
7887>

PS - "Cube Guru" is a title assigned to members based on number of posts :)
PPS - if you click "Posted", next to the date/time stamp at the top of every
post, it pops up a window that tells you the exact link to that post!

Hope this helps!

Laurie
-- 
Founder, Editor, FAQ-checker
http://www.cubeowner.com
Home of The Mac Cube FAQ!
AOL IM/iChat: cubeownernyc


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