- DVD Format
With Single Layer and Dual Layer media, all drives reported more or less, similar average speeds. So it seems that the USB interface did not have much of an affect on the LiteOn's transfer rate except in the case of SL media, where the end speed for the LiteON SOHW-1653S (i.e. the internal drive), had reached 16.27X and an average speed of 12.16X.
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. In this case, the LiteOn was the faster reader, but with negligible speed differences.


Here we can see that the LG drive reported the highest speed with +R and -R media, while with +RW and -RW media, all drives had the same speed. Once again, the speeds are the same for the internal and the external LiteOn drives.
- Appendix
Nero CD-DVD Speed Graphs