In the following tests, we examine the DVD reading capabilities of the LiteOn SHW-1635S drive with scratched / defective DVD media. For the tests we used CDVD Benchmark and Nero CDSpeed. The reference test media comes from ALMEDIO.

- Single Layer media

ABEX TDR-821

This is a single sided, single layer DVD-ROM with 4.7GB capacity, and its surface has an artificial scratch of dimensions varying from 0.4 to 3.0 mm. The following transfer rate picture comes from the CDVD Benchmark v1.21 transfer rate test.

Excellent reading, with no drops in speed and the drive managed to reach its max reading speed of 16X.

ABEX TDR-825

This is also a single sided, single layer DVD-ROM of 4.7GB capacity. The data structure of the disc is exactly the same as that of the TDR-821, with the difference that there are no scratches on it but instead, defective areas of dimensions ranging from 0.5 to 1.1 mm. There are also fingerprints sized between 65 and 75 micrometers.

Typical reading graph for all LiteOn drives, where the reading speed drops at the beginning of the second defective area, while it managed to complete the test without any significant reading anomalies. Once again, all the way up to 16X.

- Dual Layer media

ABEX TDR-841

This is an 8.5GB dual layer, single sided DVD-ROM disc with artificial scratches of dimensions ranging from 0.4 to 3.0mm, on both layers.

Excellent performance. Both layers were read without errors. Note here that due to the max supported reading speed for DL media, the drive maxed out at 8X.

ABEX TDR-845

This test disc is a single sided, dual layer DVD-ROM disc with a capacity of 8.5GB. The only difference between the TDR-845 and the TDR-841 discs is that the first includes defective areas and fingerprints. The dimensions of the defective areas ranges from 0.5 to 1.1 mm and the fingerprints are sized from 65 to 75 micrometers.

Last graph, and the hardest to read, with two layers and four defective areas (two on each layer) and the LiteOn 1635S did quick work of this test media, reading it flawlessly once again, with only a drop in reading speed reported near the beginning of the second defective area on both layers. Seems like the fingerprints present a minor obstacle for the drive. Other than that, we can say that we have a job well done.

ABEX TDV-541

The TDV-541 is a single sided, dual layer DVD-VIDEO disc, with a capacity of 8.5GB. The disc is based on the TDV-540 series which is designed for inspection and adjustment of DVD-VIDEO players. The disc checks the layer switch operation from layer 0 to layer 1 and also includes test pictures and test signals for DVD sound files. The current TDV-541 also checks the error correcting capabilities of the drive and includes scratches from 0.4 to 3.0 mm.

Excellent performance with this test media. Not much else to point out here as the above graph speaks for itself.

ABEX TDV-545

The TDV-545 disc is based on the TDV-540 series. It is a single sided, dual layer DVD-VIDEO disc with a capacity of 8.5GB. The TDV-545 includes artificial black dots on the data surface, sized from 0.4 to 1.0 mm. It also has 65 - 75 micrometer fingerprints.

Once more, the drive showed its best when reading this media.

- Conclusion

All the above tests indicate a very good error correction mechanism, with fingerprints being the only defect the 1635S has any problem with, if it can be considered that. The drive successfully completed all reading tests.