- Why shouldn't a certain tension be exceeded when one overclock?
As we saw, the fact of increasing the tension causes to make increase the load to be dissipated. Out the silicum, which composes Wafers of our processors, as any semiconductor is more “éfficace” at low temperature which has élévée temperature.
When the temperature increases on the surface of the core (the heart of the processor), of the electromagnetic disturbances are more important. They pertubent the path of the current within this one, and of is done, the processor will generate errors beyond a certain margin, which one calls max Operating Temperature. When the frequency, or the tension exceed the tolerance level of the processor, it to create errors, it is instability. The operating system is put in protection, it is the blue screen (for Windows), or the freeze.
At a certain moment, one arrives at a wall such as the frequency ratio/temperature/cooling is too high so that the increase in the tension changes there though it is. Worse, it makes heat the processor, and makes it still more unstable. The only manner of finding a stability, is to improve cooling.
If, even with a processor of which all the adjustments are defined by defect, the temperature exceeds a certain threshold, this one will generate érreurs.
The second point which makes that the temperature influences the stablity of the processor is related to the resistivity. The resistivity of silicon, like known as higher, returns it less éfficace. It less lets pass the current, and once again, that creates érreurs. We will see low why the allied temperature perhaps invaluable in the rise in temperature.
- What is resistivity?
Resistivity of a material with for unit ohm.meter, i.e. the electric resistance which it develops per meter.
The resistance of a material is calculated graçe with the formula:
That is to say:
R: Resistance
p: Resistivity
L: The length in meter
S: The section in meter-square
The resistivity of materials depends on their temperature:
That of metals varies according to heat, one will be able to take for example the tungsten filament of a bulb, whose cold resistivity is lower than that hot. It is besides for that that it reddens (like any resistance of heat) and thus which it produces of the light. If it let as much pass the hot current that cold, it would not occur a light.
For the semiconductors, the resistivity diminiue strongly with the temperature. One speaks about supraconductivity (quasi null resistivity) when that the temperature of a semiconductor approaches the absolute zero (0 K/-273.15°c).
What interests us here, it is precisely the relation temperature/resistance/resistivity:
Within the framework of the overclocking, one with tendency to increase tension and frequency, and thus thermal load.
With traditional systems of cooling, one will never go down in lower part from the ambient temperature. The only systems able to go down under the ambient temperature are the systems with phase shifts.
Briefly, to include/understand their operations:
One with a closed loop which contains a diphasic element (freon), three key points in this system, compression, condensation, and relaxation. It is at the time of this relaxation, that one “creates cold”, éxactement, slackens it (liquid state with gas = Evaporation) of the freon, which intervenes, it intervenes at the time of a change of pressure, forces it to cool, and so it absorbs a certain quantity of heat in its environment.