The transfers with size more than 1024 bytes and less than 3073 bytes per microframe are called high-speed high bandwidth transfers. In order to see best performance under this requirement, it is recommended to use Windows XP. Windows 2000 does not have good support for high bandwidth isochronous transfers. The drivers included with the Windows 2000 do not support high-speed, high bandwidth isochronous transfers efficiently (it is not robust). It will require higher CPU utilization on Windows 2000 SP4 as compared to Windows XP, and this apparently will not be fixed in Windows 2000. So we recommend using Windows XP if testing is done with high-speed high bandwidth transfers.