In the following tests, we examine the DVD reading capabilities of the NEC ND 4571A 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.

Reaching a max reading speed of 16X the drive did not drop its reading speed, managing to achieve a flawless reading, with minor drops of speed while reading over the defective area and during the end of the reading.

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.

Same perforamcen with this media, were the drive managed to read all the way to the end , with minor drops of speed near the completion.

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.

Max reading speed achieved was 12X with this artificially defective media, were both layers were read flawlessly.

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.

Same performance here. The NEC 4571A is defenitely a good reading device, with very good error correction capabilities.

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.

With the 541 test media inserted, the drive droped its speed during the layer change, and moved on with the reading all the way to its end at its normal speed. Max speed was 12X as with all DL media.

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.

Excellent performance here with the drive managing to complete the reading without a single drop of speed.

- Conclusion

Summing up, the NEC 4571A is a very good reader, with good error correction mechanism and a fast one. All sinlge layer artificially defective media were read at 16X while DL media were read at 12X, the speeds that the drive supports for these kind of media.