CD-ROM drives are rated in terms of their data transfer speed. The first CD-ROM drives transferred data at the same speed as home audio CD players, 150KBps, referred to as 1X. Soon after, CD drives rated as 2X
drives that would transfer data at 300KBps appeared. They increased the spin speed in order to increase the data transfer rate. This system of ratings continued up until the 8X speed was reached. At that point, the CDs were spinning so fast that there was a danger of them flying apart inside the drive. So, although future CD drives used the same rating (as in 16X, 32X, and so on), their rating was expressed in terms of
theoretical maximum transfer rate; 52X is widely regarded as the highest multiplier for data CDs. The standard DVD-ROM 1X transfer rate is 1.4MBps, already nine times that of the comparably labeled CD-ROM. As
a result, to surpass the transfer rate of a 52X CD-ROM drive, a DVD-ROM drive need only be rated 6X. DVD transfer rates of 16X at the upper end of the scale are common. The 1X transfer rate for Blu-ray is 4.5MBps,
roughly 3 1?4 times that of the comparable DVD multiplier and close to 30 times that of the 1X CD transfer rate. It takes 2X speeds to properly play commercial Blu-ray videos.
Optical Drive Data Rates