think they have 80 wires in the cable itself and must be fitted correct way around
Blue ide cable end must go into mobo - the old 40 pin cables have black connectors throughout and can go either way round but not the udma ide leads.
Think it's to do with being able to write as well as read at same time through the ide device/cable when fitted and properly enabled on the operating system
that is about my limit on techy ide interface leads - I plug it in, it works that is all I need to know rather than get a detailed breakdown from google n such like
on ya pc all ya need to know is
if it takes you 8 mins or more to burn a cd at max
or
if it takes around 45 minutes upwards to do a full dvd
then ya running in POI mode and not dma fully enabled
the xbox should be able to do it easily but god knows how ya turn the sodding thing on

heck I got dma enabled and running sweet on old pentium 1 / socket 7 pc's - even the really old non-mmx pc's with win98se <