Undervolting the CPU - what's in it?

In this practical tip, we explain what the undervolting of the CPU of a PC or notebook brings. We also show in which cases it makes sense and when not.

PC & Notebook: Undervolting of the CPU - useful or not?

With undervolting (or "undervolting"), the supply voltage of the CPU is lowered in a targeted manner.

• Undervolting leads to reduced power consumption. The CPU warms up more slowly and less energy is used. Due to the lower heating, the PC fans can work more slowly or do not have to be switched on; the PC runs quieter.
• Undervolting is therefore mainly used in notebooks to increase the battery life. However, it is also possible with normal PCs. This is no longer possible with newer devices.
• For higher clock rates of the CPU, a higher voltage is required so that the transistors switch through faster. If you reduce the voltage, you also reduce the clock rate. Newer PCs and notebooks do this automatically. However, you should not readjust by hand and lower the voltage at your own discretion, as this leads to serious calculation errors and a complete crash.
• The processor is in sleep mode most of the time and the CPU cores are then switched off. Undervolting has no effect here. If the processors are used, the cores are usually not fully utilized. Nevertheless, parts of the energy-saving mode continue to run. But if you reduce the voltage by undervolting, you accept that the energy saving functions will no longer work. Therefore, you should definitely not do this.
• You shouldn't do this, especially with a notebook, because this is where the display consumes the most power. If you now reduce the voltage of the CPU, energy saving functions can no longer be used and the PC consumes more power.

What to do if the CPU is under high load?

In the next practical tip, we will explain how quantum computers work.