The VIA USB 3.0 Root Hub is a component of the VIA USB 3.0 controller, which is used to enable USB 3.0 (also known as SuperSpeed USB) support on your system. It allows devices such as external hard drives, flash drives, and other peripherals that support USB 3.0 to operate at higher data transfer speeds (up to 5Gbps) compared to the older USB 2.0 standard.
In Windows, the VIA USB 3.0 Root Hub is essentially a system driver that enables the USB 3.0 controller hardware to work with your operating system. If you're having issues with your USB 3.0 ports, it could be due to a missing or outdated driver for the VIA USB 3.0 Root Hub.