I have a P4 with a SATA 160 drive. I added a 250G ATA drive I had kicking around. Had a bunch of trouble getting it to boot off the SATA drive, but resolved that. The 250 is on the 0 bus, while the SATA 160 is on the 2 bus. Now it takes over 15 minutes to boot up and the computer is nearly unusable with any application. Does SATA and ATA drives not mix? Is there some secret about adding a ATA drive that I don't know bout?