I'm having an identical problem with my new setup. When using a 160 GB Western Digital External USB drive, it tells me I have a "HI-SPEED USB Device attatched to non-HI-SPEED Hub"
Tried installing drivers from CD, it pops up a text file saying SP2 comes with USB 2.0 drivers. I can't even find another application that installs HI-SPEED USB Controllers.
Asus A8N-SLI Deluxe, AMD Athlon 64 3500+, 1GB Corsair PC4400 XMS RAM, BFG 6800 GT. Win XP SP2.