ASUS A8N5x why my USB interface is only 1.1 speed

I just returned from the machine brings the winxp drive system is also in the official on-line under the surface there is no problem, then U can be set only on the rate of 1.1, why??

is no need to use the interface front, front-mouth is often due to cable problems can only be 1.1, just behind the front just behind with 1.1 ah it is not enough to see if
Version only support USB 2.0.A lot of people have recently asked this question …the motherboard Southbridge chip does not work for you ….“ `