Which part of the computer maintains configuration data when the power is off?

The CMOS setup chip is responsible for maintaining configuration data when the power is turned off. This chip stores important system settings, such as the BIOS settings, date and time, and other critical hardware configuration data. It does this by using a small battery that provides power to the chip even when the computer is unplugged, ensuring that the information is retained.

In contrast, the data bus is a pathway for transmitting data within the computer and does not store any configuration information. Clock speed refers to the speed at which a processor executes instructions and does not involve storage of configuration data. The DIMM module, which is a type of memory module used for RAM, only temporarily holds data while the computer is powered on, making it unsuitable for storing configuration data during power-off periods. Thus, the CMOS setup chip is the correct answer as it uniquely performs the function of retaining vital configuration information when the computer is switched off.