CD - ROM purchase! Just like hard disk drives, CD-CD - ROM comes in all kinds of SCSI controller and the IDE. However, unlike hard drives, the speed and limited access of the CD-ROM drives (typically for 150ms CD-ROM drives compared to 10ms for a typical hard drives) does not stress the capabilities of either the standard transfer rate. Can be both IDE and SCSI controllers handle easily, "slower than the hard disk is" even faster transfer rates drives CD - ROM, So do not look at the decision to IDE or SCSI in terms of performance. In fact, currently the fastest drives available with EIDE 24X and a fast 90ms access times, on average, from both Hitachi and Toshiba.