🚀 go-pugleaf

Cooling Guy wrote:
> 
> Mike H wrote:

[snip]

> Whoa the max temp that most chip makers say their chips will work ok at
> is 153F not 212F and 302F. At 100 or 150 C your chip would fry your mobo
> would fry and your case temp would be sooo hot anything close by would
> fry too. Then you will see some poping!
> 
> For cooling solutions try my page at http://www.thermalnet.com
> 
> Patrick

Have peoples' brains gone on holiday or something? There are several
parameters restricting the operational speed of a (digital) microchip.

As you increase the speed, the chip heats up, but also, you start to get
close to where race conditions may occur in the digital circuits in the
chip (we are only talking digital here - after all, why would you clock
a *purely* analouge chip?).

The whole point of having a clock signal is to co-ordinate the logic
gates in the chip so that states change in an ordered fashion. If you
increase the clock too much, it starts to suffer from propogation delay
through the chip (ie it gets out of phase as it is transmitted through
the clock track - hey presto - buggered up timing - inoperable chip). In
addition to this, the clocking will loose the ability to prevent race
conditions occuring on the chip - once again, inoperable chip.

On top of that, the chip gets hotter. This changes the conductive
properties of the silicon such to the eventual stage where depletion
regions in individual gates form even when there is no appropriate gate
threshold voltage being applied - inoperable chip.

Finally, all of the above have not yet destroyed the chip (you can turn
it off, let it cool then use it again). However, if you let the chip get
too hot for too long, the impurities in the silicon will 'leak' into the
intrinsic silicon (pure silicon) and into the 'other' impurity areas
(similar to sideways growth), thus changing the conductive properties of
the chip permanently. Mind you, if the temperature gets hot enough, very
large channels will form in the transistors, allowing huge currents to
flow thus blowing the chip to kingdom come.

So you see, heat is only a small part of the equation.

Mind you, the latest Cray Supercomputer being used at Edinburgh
University requires a rather non-humble 210 *gallons* of coolant to be
pumped around in order to keep the circuitry within operational
temperature ranges! That's what I call a thirst!

a.

-- 
Andrew Bruce                   | mailto:abruce@sqf.hp.com