Zevia helped me out on this with a bunch of suggestions.
I ended up trying 2 different Firewire cards (imbedded with my sound card and independent) along with the USB2.0 on my mainboard, and a PCI expansion card. I was never able to get 16x.
I've got a an XP2000 with 1gb of ram. My burst tests with firewire were 32mbs but with USB2.0, I was only able to get 24.
I ran out of ideas, but feel free to offer up some more goodies. I'll try anything! Thanks.