I have bought 3 Maxtor a 8,13 and 15 all ata 66. The 15 I sent back twice and I have never been able to set anyone of them up for ata 66 in any of my 3 Abit bh-6, BP-6 and BE-6-2 motherboards. I've just lost the 15 for the third time although I managed to reformat it. Since it's Christmas I think a new Seagate or Western Dig is in order for me.