With Windows 8, Microsoft is integrating an eXtensible Host Controller Interface (xHCI) driver, which serves as a common driver for USB 3.0 host controllers. Expreview put this driver to test with a Renesas USB 3.0 controller, and compared its performance to when the controller is backed by Renesas' own driver (ver. 2.1.28.0). The controller is a μD720200F1 found on ASUS P8P67 Deluxe motherboard. The reviewer used Orico UE3 16GB USB 3.0 flash drive that uses SLC NAND flash memory.

The flash was put through four synthetic tests on a constant hardware setup, differences in performance were attributed to the drivers. Tests included HDTune, ATTO, AS SSD, and CrystalDiskMark. The xHCI driver provided by Microsoft trailed a tiny/insignificant notch behind the third-party driver provided by Renesas. In HDTune, the performance graph was smoother (fewer variations) with the Microsoft xHCI driver. In sequential speed tests, variation between the two drivers seldom exceeded 2%. The xHCI driver will ship with Windows 8, letting you run USB 3.0 host controllers and compatible devices right out of installation. The drivers pass through Microsoft's WHQL, although the update cycle of drivers provided by Microsoft is traditionally known to be slower, in some cases they have found to be more stable. Screenshots with "MS" markings (below) show results for the xHCI driver.More results follow.