I have been doing considerable research on this question, but I wish to get a clear idea about the solution: I have a DVD and a CD drive on 1st IDE channnel. These work in UDMA 2 mode. On 2nd IDE channel I have a HD Maxtor 80 GB as master -system disk- and a HD Maxtor 180 GB as slave. Both are in UDMA 2 mode. These are recently bought 7200 RPM drives capable of working in UDMA 6 mode. But until now try as I might I could not bring them to UDMA 6 mode. My MOBO is ASUS P4P8SX under WIN XP Prof. I haver upgraded the BIOS, upgraded the SIS IDE drives, updated everything on Win XP and so on. i am probably missing something very obvious but what? Any help will be highly appreciated.