I know I'm a n00b by post count, so this post may not go over very well. However, with the constant bickering back and forth between resistance verses temperature, I figured I would throw in my 2¢ here.
I have successfully completed 3 years of Physics, and 2 years of Chemistry. Allow me to quote a specific paragraph in my textbook in relation to temperature vs resistance.
"The resistivity, and hence the resistance, of a conductor depends on a number of factors. One of the most important is the temperature of the metal. For most metals, resistivity increases with increasing temperature. [yes, it says most. however, thermistors increase inversely, but we are not discussing thermistors when we're talking about CPUs.] This correlation can be understood as follows. As the temperature of the material increases, its constituent atoms vibrate with increasingly greater amplitudes. Just as it is more difficult to weave one's way through a crowded room when the people are in motion than when they are standing still, so do the electrons find it more difficult to pass atoms vibrating with large amplitudes. The increased electron scattering with increasing temperature results in increased resistivity."
Take this equation (reading po and To as P-sub-zero and T-sub-zero):
p = po[1 + a(T - To)]
p = the resistivity at a certain temperature T.
po = the resistivty at some reference temperature To.
a = temperature coefficient of resistivity.
Here are some temperature coefficient values for some common materials, and their resistivity at 20 degrees Celcius:
Material, Temperature Coefficient, Resistivity
Silver, 3.8x10^-3, 1.59x10^-8 ohm*m
Copper, 3.9x10^-3, 1.7x10^-8 ohm*m
Lead, 3.9x10^-3, 22x10^-8 ohm*m
If you were to take, say copper, for example, you would get this equation:
p = 1.7x10^-8[1 + 3.9x10^-3(T - 20)]
If, for example, we wanted to compare the resistivity of copper at 0 degrees celcius verses 20 degrees celcius, we only need to input 0 for T, and solve for p.
p = 1.7x10^-8[1 + 3.9x10^-3(0 - 20)]
p = 1.5674x10^-8 ohm*m
As you can see, the resistivity of copper was much lower than when it was at 20 degrees celcius. (92.2% resistivity compared to 20 degrees celcius.)
As far as superconductors, they work in the exact same way as the previously mentioned materials. The only difference is that their resistivity only works when the metal is above a certain "critical temperature". Anything below the temperature and the superconductor had zero resistance.
And as far as thermistors are concerned, which work with resistance inversely proportional to temperature, they have a negative temperature coefficient, which is the reason that they seem to have a lower resistance as temperatures increase. However, thermistors are rare compared to the common material, which increases proportionally to the increasing temperature.
Processors are made of material with a positive temperature coeffiecient. Thusly, as temperatures increase, resistance increases. That is the reason that as people try overclocking their CPUs and temperatures increase, they have to begin upping their voltage to overcome the increased resistance. Similarly, as CPU's are cooled, resistance is lowered. Hence, the cooler you can keep your CPU, the less voltage you need to pump through it, and the better off your CPU is. You're not going to kill your CPU by having it -30 degrees celcius. That is, unless you lower the temperature from, say, 30 degrees celcius to -30 degrees celcius in a fraction of a second. If that happens, then you get into the subject of thermal expansion and contraction, which has absolutely nothing to do with resistance in the first place.
So, case in point, resistance increases with temperature, decreases with a decrease in temperature. Keeping your CPU at an extremely cool temperature is not going to hurt it. Electricity will flow through it better, and all will be good.
Like I said, this may be taken with a grain of salt, since I've only got one post. However, I have been lurking throughout this forum for a good while, and read this topic through all the way, and figured that it would be best to join and post what I know, to try to end this controversy.
Have a great day (or morning, since it's 5:00am and I haven't even gone to bed yet, and need to be up in 5 hours), and enjoy overclocking with greatly cooled CPUs!
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