On 19 Mar 98 at 21:22, Lindstrom, Rick wrote: > The builder slaved the CD-ROM drive to the hard drive, with both > on the primary IDE port on the MOBO. Besides the fact that this > will make it difficult to add another drive at a later time, my > understanding is that doing it this way will compromise the > performance of the HD. Something about the IDE port being no faster > than the slowest device attached to it, which in this case is the > CD-ROM drive. IDE/EIDE devices run the channel in various "PIO modes". Traditionally, the channel would only run at the fastest mode supported by both devices, and (also traditionally), CD-ROM drives didn't support much more than mode 1. Both of these traditions seem to have faded over time. Modern CD-ROMS support higher PIO modes, and it appears that some modern chipsets -- this may be tied to UDMA support -- can switch mode depending on which device is being addressed. So if this is a new machine (430TX, 440LX?, VP3?), this is probably not an issue. If it's an older machine AND an older CD-ROM drive, this might be a concern. David G