VRM stands for Voltage Regulator Module and is located close to the CPU socket to provide a reliable and clean power supply. The VRM regulates the power from the PSU. In overclocking you modify BIOS settings to instruct the VRM for increased performance at the expense of increased heat output. Motherboards for overclocking come with a high-quality VRM that uses better components. But a VRM always consists of MOSFET's, Chokes, Capacitors, and a PWM Controller. The IC(Integrated Circuit)is there to control and regulate those components.