You can be sure, however, that it is slow. It's interesting to contrast this situation with that of hard drives. It's the data transfer rate they have no idea about. Even with 32x CD-ROM drives, the average time it takes to reposition a drive's read head to a new location and start reading data is at least 100 milliseconds. Compare that with the under 10 millisecond access times of today's hard drives.
Access time is the other piece of the CD-ROM drive performance puzzle.
Data on a CD-ROM is recorded in equal length sectors on a single spiral track that starts at the inner edge of the disc and finishes at the outer edge. This track is on the order of .6 microns wide, with a turn spacing of 1.6 microns. A micron, if you don't happen to remember, is equal to a millionth of a meter. A human hair is about 100 microns in diameter. A CD-ROM has a track density of about 16,000 turns per inch if you measured across the disc.