The pexusb3s23 2 port pci express usb 30 card lets you add two usb 30 ports to any pci express enabled computer system with an optional sata power connector to connect to your system power supply and deliver up to 900ma of power per port to usb 30 bus powered devices 500ma for usb 20 the pcie usb 30 adapter is compliant with usb 30 standards for data transfer speeds up to 5 gbps while still offering backward compatibility with existing usb 20 11 devices for added versatility the controller ca