Which component is essential for retaining BIOS settings on the motherboard?

The component essential for retaining BIOS settings on the motherboard is the CMOS battery. This small battery, typically a CR2032 lithium coin cell, powers the CMOS chip, which stores BIOS settings and system configuration information. When the computer is turned off, the battery provides the necessary power to maintain these settings. This allows the computer to remember important configurations such as the clock settings, boot sequence, and hardware settings even when unplugged from power.

Without the CMOS battery, all custom settings would be lost each time the system is powered down, leading to misconfigured hardware and incorrect date and time settings when the system is restarted. Other components, while crucial for the overall functioning of the PC, do not directly contribute to the retention of these critical BIOS settings.