> CPU
> ------------
> Foam Heat Transfer Pad
> ------------
> Aluminum Block Heatsink <-------> Heat Pipe
> ------------
> EMI Shield (aluminum sheet covering bottom except battery bay)
> ------------
> Plastic Case Bottom
Thanks, Tim, that was a great post as usual, but I've got my back up now
and am going to beat this dead horse one last time.
Guess I wasn't clear but I wasn't proposing replacing the foam heat
transfer pad with alumium foil but as a shim between the pad and the
heatsink. Thus:
CPU
------------
Foam Heat Transfer Pad
------------
folded aluminum foil
------------
Aluminum Block Heatsink <-------> Heat Pipe
------------
EMI Shield (aluminum sheet covering bottom except battery bay)
------------
Plastic Case Bottom
If you take a 4"x5" square of foil, fold it in half 5 times, each time
carefully burnishing it flat you end up with about a 0.2mm thickness. The
point of the foil is to simply provide a firmer contact from the pad to the
heatsink. I don't think IBM manufacturing tolerances are that tight and in
my case my 2400 benefited from it.
As far as air, there isn't going to be any. With time, hot/cold cycling and
the pressure of the weight of the circuit board on the foil whatever air
you left when you burnished each fold will disperse. As far as heat
conductivity, at 0.2 mm of thickness, the difference between the heat
conductivity of aluminum and any other metal you care to name isn't going
to be of significance.
I would have let go of this a long time ago if it were idle speculation,
but I've done it and it did lower my cpu temp 10 -15 degrees.
I'm done now, thanks for indulging me <grin>
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