In the following tests we examined the DVD reading capabilities of the Plextor 740A drive with scratched / defective DVD media. For the tests, we used CDVD Benchmark and Nero CDSpeed. The reference test media comes from ALMEDIO. These tests were made prior to the release of the 1.01 firmware upgrade and were not re-tested, as the latest firmware does not improve any error correction issues.

- Single Layer media

ABEX TDR-821

This is a single sided, single layer DVD-ROM with a 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.

As it can be seen from the above graph, the drive completed the test, managing to read over the defective areas without producing any errors. The resultant graph is not the cleanest with a lot of speed fluctuations towards the end of the disc.

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.

Again, same behaviour with this test media. The Plextor drive managed to read through both defective areas and completed the disc without producing any errors. But there's a lot of speed fluctuating going on near the end of the disc.

- 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 reading with this inserted test media.

ABEX TDR-845

The disc is a single sided, dual layer DVD-ROM disc of a capacity of 8.5GB. The only difference between the TDR-845 and the TDR-841 is that the first includes defective areas and fingerprints.

The dimensions of the defective areas range from 0.5 to 1.1 mm and the fingerprints are sized from 65 to 75 micro meters.

Same performance here. No fluctuations in speed, reading speed nearly maxed out at 13X. Excellent performance.

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.

The defective media was read all the way to the end by the 740A, with a few drops in speed, which however did not produce any errors from the drive, indicating once more good error correction capabilities.

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 has also 65 - 75 micro meter fingerprints.

Last test with defective media and once again, we have flawless reading, all the way to the end. Excellent performance in this case too.

- Summary

We saw the PX - 740A doing extremely well with the CD error correction tests in the previous page, and it did similarly well here with DVD error correction, managing to read all inserted test media flawlessly, indicating great error correction mechanism.