I must be hallucinating then. I just connected my DAC-02 to one of my USB3 ports (HP Pavilion HPE H8-1240t /Windows 7) (with a USB2 cable fwiw) and it is playing back fine !
My USB2 external drives all work fine on USB3 ports
YMMV of course !
Edited by nick_charles - 11/4/13 at 4:27pm