A: Because the SM Bus is a core part of the chipset. Dell bundles it into the larger Chipset Driver Package to ensure all motherboard components are installed simultaneously.
You will not see a driver literally named "SM Bus Controller." Instead, look for these package names: sm bus controller driver windows 10 64 bit dell
To resolve the SM Bus Controller driver issue on your Windows 10 64-bit Dell: A: Because the SM Bus is a core part of the chipset