On a 2004 vintage Antec SX series case, I was surprised to find out that while the rear ports on the motherboard supported high speed USB 2.0 operation, the front ports limited the USB device (iPod) to USB 1.1 speed (“full speed”). I checked and rechecked the wiring.
I came across the following posts which described a similar problem, USB 2.0 devices are unable to connect to the front ports or simply don’t work. This is due to a no-connect pin being connected to the front USB panel. The solution is to remove the header pin or cut the wire going to that pin.
Then I found the solution to my precise problem: USB 2.0 devices only work in slow speed on the Antec cases. The solution is to remove and bypass the filter circuit on the small board containing the front USB and firewire ports! It looks like Antec may even offer a free upgrade of the front USB board to one that operates correctly with USB 2.0 devices, so it doesn’t hurt to ask at Antec’s tech support site.