- CD Format

Like the 1693S, the LiteOn SHW 1635S supports up to 48X reading speed for both pressed and CDR media, while it can read USRW media at up to 32X. The following graphs show the maximum reading speed the drive managed to achieve with the various CD media, as well as the reading speeds of the comparison drives.

LiteOn drives have always been fast CD readers and the 1635S is no exception. In the CD reading tests, the results of which are shown above, the reviewed drive managed to achieve the fastest reading speed managing 37.67X average speed compared with 36.36X and 32.07X for the NEC and Pioneer drives respectively. With USRW media, the NEC reported the fastest reading speed due to its max 40X supported speed.

- DVD Format

We repeated the reading tests, this time using a collection of pressed SL and DL DVD media to test the drive's reading capabilities with DVD media and we present the results in the graphs below.

All three drives support up to 16X reading speed with Pressed SL media, hence the difference in speed is negligible.

The two layers of a PTP DVD-ROM disc are read sequentially with the drive starting reading from the inner part of the disc, which is the beginning of each layer, progressing towards the outer range, for each layer. Max supported speed with the 1635S is 8X, while with the NEC and Pioneer drives, max supported speed is 12X.

The graph above shows the reading performance of the drive with OTP dual layer 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 tested previously. The difference here is the reading strategy of the second layer of 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. Similar performance in this case due to the 8X max reading speed with DL media.

With Write-Once media, the 1635S reported lower reading speeds than the NEC drive which was fastest. With ReWritable media, the LiteOn and NEC drives reported similar speeds while the Pioneer drive was left behind. In general, speeds with DVD +/- R and RW media were very consistent at just above 9X from the LiteOn drive.

Even though the ripping speed is not the highest, it is nonetheless a fast speed.

Overall, good reading capabilities, excellent CD reader and a fast DVD reader.

- Appendix

Nero CD-DVD Speed Graphs

• CD Pressed / CD-R / US-RW
• DVD Pressed SL / DVD Pressed PTP DL / DVD Pressed OTP DL / DVD-R / DVD-RW / DVD+R / DVD+RW