- CD Format
The Plextor 740A drive supports up to 48x reading speed for CD media.



All drives managed to achieve their specified maximum reading speeds with all three tested media. Speed differences reported are negligible. except in the case of 24X USRW media, where all drives except the LiteOn reached 40X maximum reading speed. The LiteOn supporting up to 32X with RW media.
- DVD Format

Once again, but this time using DVD pressed media, the transfer rate graph above shows no significant speed differences between all four drives.

The two layers of a PTP DVD-ROM disc are read sequentially
with the drive starting the reading process from the inner part of the disc, which is the
beginning of each layer, progressing towards the outer range for each layer.
Here too we see that all drives reach their specified maximum speeds of 12X except for the LiteOn which supports 8X with DL media.

The first layer of an OTP dual layer DVD-ROM is read exactly
the same way as the first layer of the PTP disc we tested previously. The difference
here is the reading strategy of the second layer on the disc. The beginning
of the second layer is located in the outer part of the disc, so the drive
starts reading from the outer tracks towards the inner part of the disc. Same case as before with all drives reaching their maximum speeds of 12X for the Plextor, BenQ and NEC drives and 8X for the LiteOn.
The three drives from Plextor, BenQ and NEC, all support up to 16X reading speed with DVD+R/-R media, and thus managed to achieve the fastest times. All three drives reported more or less similar speeds.
The fastest ripper proved to be the Plextor drive, followed closely by BenQ. Nice ripping speed results.
Before moving on, notice here that in all the above tests, the BenQ and Plextor drives, report very close results. This is due to the fact that they both use the same chipset.
-Appendix
Nero CD-DVD Speed Graphs