The ATI SMBus Windows driver is a device driver that facilitates communication between the system's SMBus (System Management Bus) controller and the operating system. The SMBus is a communication protocol used for managing and monitoring system components such as sensors, memory modules, and power-related components. The SMBus is often used by motherboards to monitor various system parameters like temperature, fan speeds, voltage levels, and battery status.

The term ATI SMBus driver typically refers to the SMBus controller integrated into ATI-branded chipsets, which were commonly used in older AMD/ATI systems before they were merged under the AMD brand. These chipsets include both northbridge and southbridge components, with the southbridge often handling the SMBus interface.