could you send me the output of pci from your plan 9 machine? it would also be helpful if you could copy down the output of the e820 scan and send that along. sata (ahci) should be supported on your machine, i believe.
on a laptop, i don't think one would notice a difference in transfer rate. the main advantages of sata are support for more than 4 devices and support for more than 2 devices on non-shared links and support for hot plugging. it is also easier to mix pata & sata drives if the sata drives are treated as sata drives. - erik
