The risks of overclocking

The risks of overclocking

Basic knowledge

To understand the risks of overclocking we have to take a look at the physical basics of your CPU/GPU. Processors contain millions of transistors which are made out of doped silicon.

Raw silicon

Raw silicon

SEM shot of a transistor. [source: FBH-Berlin]

SEM shot of a transistor. [source: FBH-Berlin]

Silicon and change of Temperature

Silicon is a semiconductor which means that it’s naturally not conductive. However if you add few atoms such as boron, it will become partially conductive. Another characteristic of silicon is that the electrical resistance is decreasing with an increasing temperature, whereas the resistance is increasing in normal metals such a s copper or aluminium

Resistance of silicon compated to the temperature

Decreasing resistance of silicon with increasing temperature

The result of the decreasing resistance is a full conductivity at a certain point. This means that a high temperature of the CPU will lead to an electrical short and permanent malfunction of the processor. To prevent this you should never exceed 100 °C on any CPU or GPU. However, the maximum recommended temperature might be even lower than that to prevent permanent damages.

 

The influence of high voltage and current

Todays CPUs are being manufactured in structures close to sizes of atoms. The structure of Intels Haswell CPUs is only 22 nm thick whereas an iron atom is only about 0.25 nm thick. At this level, quantum physics is very important and there are several effects causing the degradation of a microprocessor.

Electromigration is already quite well-known in the overclocking community and caused by high current densities in very small traces. Since the traces are made out of copper, an raised temperature will increase this effect even more. Eventually, the electromigration will cause damage in traces and will lead to a permanent malfunction of your processor.

Void in a trace caused by electromigration. [Source: dwpg.com]

Void in a trace caused by electromigration. [source: dwpg.com]

However, this effect is always present and will eventually kill the CPU no matter if it was overclocked or not. It depends on the production tolerance if it appears sooner or earlier. Some CPUs will last 15 years, others only 3 years. You never know how fragile your CPU is, so just give overclocking a try and don’t worry. It could be that your CPU lasts 10 years even with overclocking. And who keeps a CPU for such a timeframe?

 

Do I lose the warranty of my CPU?

Theoretically: yes – practically: no.

Today’s processors have a dynamic voltage and also dynamic clocks (turbo). For the CPU it makes no difference if the mainboard sets the voltages and clocks by itself or if you adjust them manually.

 

Conclusion

If you keep an eye on the temperature of your CPU and stay in the recommended voltage-range there is almost no risk in overclocking. Even using stock voltages you can usually increase the clocks by a few hundred MHz with almost no risk at all.

Questions or suggestions? Let me know in the comments.

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