I had a similar, if not the same issue. It was an older version of windows on the HD i was trying to migrate some data from onto my XP machine, which the main drive was sata. I changed all the jumper settings I could, tried setting the boot priority different but it would not let the sata be...
i got roughly 10% slower response time with the standard non high-speed usb sticks compared to a wifi pci card. only tested linksys though. i cant vouch for others.