The limiting factor of the CD/DVD drives was seek time, not read speed. Seeking a spot on the disk was on the order of 150ms. You basically got 5-7 read OPS.

The limiting factor of the CD/DVD drives was seek time, not read speed. Seeking a spot on the disk was on the order of 150ms. You basically got 5-7 read OPS. The best drive I remember stood out at 120ms seek, some would be over 200ms seek. Sometimes this was a hard number to track down. Even with a 48x drive, installation could easily still take 30+ minutes particularly if the installer wasn't optimized for sequential read off a flat file. Sometimes you got a really bad installer, and it could take a pretty grueling 2+ hours. Some companies chose to optimize for space (thus cost..) rather than user experience. As space got more plentiful it would sometimes be easier to copy the disk and remount it and then install.