I've just fitted an Seagate 40Gb HDD as a Slave to A Dell Dimension 450. I've tried FDISK with a Win ME boot disk and formated the HDD. I've tried Formatting from the XP CDrom in both NTFS and Fat32. I have installed the Disc Wizard from Seagate and for all the above options it did not see the drive. The Bios detects the HDD and donates it the correct 38Gb! The Primary Master is a 10Gb HDD so I don't think the ATA speed is too much of a conflict here.