VCore

The CPU core voltage (V_CORE) is the power supply voltage supplied to the CPU (which is a digital circuit), GPU, or other device containing a processing core. The amount of power a CPU uses, and thus the amount of heat it dissipates, is the product of this voltage and the current it draws. In modern CPUs, which are made using CMOS, the current is almost proportional to the clock speed, the CPU drawing almost no current between clock cycles. (See, however, subthreshold leakage.)

In order to help conserve power and manage heat, many laptop and desktop processors have a power management feature that allows software (usually the operating system) to adjust the clock speed and core voltage dynamically.

Often a voltage regulator module converts from 5V or 12 V or some other voltage to whatever CPU core voltage is required by the CPU.

The trend is towards lower core voltages, which conserve power. This presents the CMOS designer with a challenge, because in CMOS the voltages go only to ground and the supply voltage, the source, gate, and drain terminals of the FETs have only the supply voltage or zero voltage across them.

The MOSFET formula: ${\displaystyle \,I_{D}=k((V_{GS}-V_{tn})V_{DS}-(V_{DS}/2)^{2})}$ says that the current ${\displaystyle I_{D}}$ supplied by the FET is proportional to the gate-source voltage reduced by a threshold voltage ${\displaystyle V_{tn}}$ which is dependent on the geometrical shape of the FET's channel and gate and their physical properties, especially capacitance. In order to reduce ${\displaystyle V_{tn}}$ (necessary both in order to reduce the supply voltage and to increase current) one must increase capacitance. But, the load being driven is in fact another FET gate. The current needed to drive it is proportional to capacitance, which thus requires the designer to keep it low.

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