Hey, I have had quite the time trying to enable UDMA in Windows XP Professional. First off, I have three drives installed in my computer. On the Primary channel, I have an IBM Deskstar 60GXP 40gigbyte ata 100 as the master and an older 44X CD Rom drive as the slave. On the Secondary channel, I have an Iomega 12 X 10 X 32 Drive as a solo master. The IBM drive operates at 7200rpms with a 2mb cache and 8.5ms time. Also, for the Primary Channel I have a Vantac 80 pin ATA 100/133 cable. So, everything should be within the specs! In Windows I have "DMA if availible" option for both channels. In my KT3 Ultra 2's bios, I have AUTO specified so it will by default it will have the highest speed! So why is this all messed up? Is the old CD rom holding back the IBM Deskstar?