Try changing out the ribon cable i just got a new 60 gig maxtor 7200 and it was stuck in pio mode.
Turns out the 80 wire ribon cable that came with it was bad i swaped it out for a 40 wire standard cable and boom dma mode heh try tfering 15 gigs with of data on to a hd stuck in pio mode hahah estimate of 1225000+ minutes doh!!!
Any how check that and let me know if it was same for you btw i never got a 80 wire that worked that came with a hd.