The SMBus Controller, or System Management Bus, basically controls power functions and other low-priority communication between the main processor and PCI cards. It only appears on Intel chipset motherboards, and is not integral to operation of Windows, but it does smooth things out once installed. Typically, the operating system has these drivers already installed, but occasionally, you'll need to download them or install them from your motherboard's CD-Rom. If you need to download them, you can go to Intel's website: www.intel.com and choose the top option: Get the latest driver. Choose your OS, and then download the top (latest) file. Simply run the file and reboot as requested, and it will not only update the SMBus controller driver, but your chipset drivers as well, which include hard drive controllers, USB controllers, and many other on-board devices.