[Richard Lawler (Unverified) Posted Feb 11th 2006 7:37PM]

Jose, I think you mixed up the MBps and the Mbps. If you look at your qoute, single speed Blu-ray is 4.5 megaBYTES per second, while 2x blu-ray is 9 megaBYTES per second, becvause blu-ray reads the same speed all along the disc.

a 12x DVD drive varies from 8 - 16 megaBYTES per second depending on where the data is being read (inner edge slower than outer edge of the disc)

You won't see single speed Blu-ray drives because it would be too slow to play the movies, check here for more info:

http://www.blu-ray.com/faq/
speeds below are in MegaBITS(Mbps), divide by 8 for speed in megaBYTES (MBps).

" How fast can you read/write data on a Blu-ray disc?


According to the Blu-ray Disc specification, 1x speed is defined as 36Mbps. However, as BD-ROM movies will require a 54Mbps data transfer rate the minimum speed we're expecting to see is 2x (72Mbps). Blu-ray also has the potential for much higher speeds, as a result of the larger numerical aperture (NA) adopted by Blu-ray Disc. The large NA value effectively means that Blu-ray will require less recording power and lower disc rotation speed than DVD and HD-DVD to achieve the same data transfer rate. While the media itself limited the recording speed in the past, the only limiting factor for Blu-ray is the capacity of the hardware. If we assume a maximum disc rotation speed of 10,000 RPM, then 12x at the outer diameter should be possible (about 400Mbps). This is why the Blu-ray Disc Association (BDA) already has plans to raise the speed to 8x (288Mbps) or more in the future. "


12x DVD speed = 16,230.47KB/s = 15.849609375megaBYTES/sec

http://www.matisse.net/bitcalc/
http://www.osta.org/technology/dvdqa/dvdqa4.htm