This make three months in a row where "sm bus controller" is one of the most searched for items on this site. The Windows install disk doesn't install the drivers for the sm bus controller. For all of you that are searching for this you did NOT install your chipset drivers yet! To get any kind of decent performance out of windows you will want to be running fairly up to date drivers of everything in your computer starting with your chipset and video card.

What is it?

Systems Management Bus. If you'd like some real tech documents about this you'll want to visit smbus.org. The less detailed explanation was found on thefreedictionary;

System Management Bus - (SMBus, SMB) A simple two-wire bus used for communication with low-bandwidth devices on a motherboard, especially power related chips such as a laptop's rechargeable battery subsystem (see Smart Battery Data). Other devices might include temperature sensors and lid switches.

A device can provide manufacturer information, indicate its model/part number, save its state for a suspend event, report different types of errors, accept control parameters, and return status. The SMB is generally not user configurable or accessible.

The bus carries clock, data, and instructions and is based on Philip's I2C serial bus protocol. Support for SMBus devices is provided on Windows 2000. Windows 98 does not support such devices.

The PIIX4 chipset provides SMBus functionality. Vendors using SMBus would be required to pay royalties.

I've only found references to the SMBus on Intel chipsets, but I'll provide links to a lot of other chipset drivers just in case.

Intel Chipsets
Link

Nvidia Chipsets
Link

VIA chipsets
Link

AMD chipsets
Link

SIS chipsets
Link