In the following tests, we checked the DVD reading capabilities of the NEC ND-4551A drive with scratched / defective DVD media. For our tests, we used CDVD Benchmark and Nero CDSpeed. The reference test media comes from ALMEDIO.

ABEX TDR-821

This is a single sided, single layer DVD-ROM with a 4.7GB capacity, and its surface has an artificial scratch varying in dimensions from 0.4 to 3.0 mm.

The following transfer rate picture comes from the CDVD Benchmark v1.21 transfer rate test.

A very smooth reading graph with no errors. A few speed drops over the fifth step in the defects area but nothing to be concerned about.

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, the only difference being that there are no scratches on it. Instead, there are defective areas, ranging in dimensions from 0.5 to 1.1 mm.

There are also fingerprints sized between 65 and 75 micrometers.

Excellent reading, no problems over the defect areas.

- Dual Layer media

ABEX TDR-841

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

The NEC ND-4551A has been improved over its predecessor in coping with DVD defects and the tests confirm this. Excellent behavior with the specific test disc. Artificial scratches are not a problem for the drive.

ABEX TDR-845

The disc is a single sided, dual layer DVD-ROM disc of a 8.5GBcapacity. The only difference between the TDR-845 and the TDR-841 is that the former 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.

Very good performance with smooth reading speed. Again, no errors were reported.

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 was designed to inspect and adjust DVD-VIDEO players. The disc checks the layer switch operation from layer 0 to layer 1 and also includes test pictures and test signals on DVD sound files.

The current TDV-541 also checks the error correcting capabilities of the drive. It also includes scratches from 0.4 to 3.0 mm.

Very good error correction capabilities, although the drop in speed over the second layer is there, just as it was with the ND 3540A.

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.

Excellent reading from the NEC drive. The artificially embedded dots and fingerprints were not a problem for the drive's error correction mechanism.

- Summary

The NEC ND-4551A has a very strong error correction mechanism and it managed to read all of our discs successfully without any errors being reported.