Hi I try to connect both the hard drive and the DVD-ROM drive on the same IDE cable. I checked the transfer mode in the BIOS of the hard drive is UDMA 6, whereas the DVD-ROM drive is UDMA 2. That means the transfer rate of the hard drive is not affected by the slower transfer rate of DVD-ROM drive, right? In other words, they are independent, right? Note that I used the 80-wire IDE cable for this connection. Thank you so much for any idea or feedback.

Of course that's right...& if someone told you differently, they don't know what they're talking about. Motherboard chipsets have been using "independent device timing" since the days of the socket 7. If all you have are those two devices though, it would be better to put the optical drive on the 2ndary channel as master. Data transfers are always more efficient between devices on separate channels, rather than between two devices on the same cable/channel. ASUS A7N8X-X Athlon XP 1800+ 8.5 x 200MHz 1024MB PC3200 2.5-3-3-7 Asus A9550GE/TD 128MB WinME/WinXP Pro SP1

Thank you Jam. That is the way I have to do. I have no other choice. By the way, when was the Socket 7 indroduced?

I think the socket 7 format made it's debut in 1994? ASUS A7N8X-X Athlon XP 1800+ 8.5 x 200MHz 1024MB PC3200 2.5-3-3-7 Asus A9550GE/TD 128MB WinME/WinXP Pro SP1

I think it's best to have the DVD-ROM drive on the same channel as the hard drive. You aren't going to be transferring data between the DVD-ROM drive and the hard drive very often. Put a burner on the other channel.

What I meant was if you only have 2 IDE devices, it would be bettwer to have them on separate channels. But I agree, if a 3rd device (burner) is added, it should be the 2ndary master & the DVD moved back to the primary slave ASUS A7N8X-X Athlon XP 1800+ 8.5 x 200MHz 1024MB PC3200 2.5-3-3-7 Asus A9550GE/TD 128MB WinME/WinXP Pro SP1