The ezusb.sys driver is the device driver for the EZ-USB chips (AN21xx, FX and FX2). It will function as the device driver with both a full speed and high speed host system. It is not the host USB driver. If your system has a high-speed host controller, the drivers for it will control the transfer speed selected, i.e. full or high speed. We do not supply the host controller drivers. You need to contact the supplier of the host controller for the proper high speed host controller drivers.