Writing Data CD-R discs:

The specifications of the ASUS DRW-20B1LT state that the drive is able to write CD-R discs at 48X and CD-RW at 32X.  

For our data writing tests, we simply burned a full disc using CD-Speed (create data disc) function and burned the discs at the maximum speed allowed.

Let us find out how the drive really performs in speed and quality.

Write quality:

We will test CD-R discs from many different CD-R manufacturers. To really measure the write speed, we used the “create data CD” function in Nero CD-Speed. The discs were written at the maximum speed that the drive supports. For the quality test, we used Nero CD-Speed’s Advanced Disc Quality Scan and combined this with a Transfer Rate Test to test if the resulting disc was readable. Also note that different drives and different reading speeds may affect the results obtained when scanning the discs. We used a BenQ DVD DW1655 with firmware BCIB under Advance Quality Scan and scanned these discs at 16X CLV speed; as well as a Disc Quality Scan at 48X speed.

There is more than one way to handle C1 and C2 error detection/correction, but a simple and common way is to detect and correct up to two errors per frame in each stage and detect three or more errors:

• E11: 1 error detected and corrected by C1 layer
• E21: 2 errors detected and corrected by C1 layer
• E31: 3 or more errors detected but not corrected by C1 layer

The sum of these (per second) is called the Block Error Rate: BLER=E11+E21+E31

• E32: 3 or more errors detected but not corrected by C2 layer

Any E31 is un-correctable by the C1 layer and will result in the bytes in that frame being redistributed into multiple frames which are passed to the C2 layer.

Any E32 is un-correctable by the C2 layer and will result in interpolation being used for Audio CDs or will result in third layer error correction being use for Data CDs.

Different drives have different ways of reporting these errors in a Disc Quality scan.  Lite-On CD-RW drives will report C1 and C2 errors this way:

• C1=BLER=E11+E21+E31
• C2=E32

BenQ DW1650 Disc Quality

• C1=BLER=E11+E21+E31
• C2=E32

BenQ DW1655 Advanced Disc Quality

• All errors are reported separately as well as BLER=E11+E21+E31

Here is an easier way to look at Disc Quality Scanning:

A written CD-R disc will always have some C1 errors; C1 errors are easily corrected by the drive’s error correction capabilities. The next level of errors is C2, while C2 errors could also be corrected by most drive’s error correction capabilities; they are not wanted on a good quality disc. A good disc should not contain any C2 errors, and preferably have an average C1 error amount of below 2.0 for the best discs, or at least below 10.0 averages for good quality discs. After C2 errors, there are only un-correctable errors that will make a disc unusable.

So, in short, our analysis will be based on these guidelines to determine the quality of the burned discs which will be Quality Scanned on our BenQ DW1655:

CD-R/RW quality scans guideline

Below are the obtained results:   

Quality Scan with BenQ DW-1655

TRT with the BenQ DW-1655

The ASUS DRW-20B1LT burned this test media with C1 average errors of 7.73.

Quality Scan with BenQ DW-1655

TRT with the BenQ DW-1655

The HP media manufactured by CMC Magnetics has burned with good quality.

Quality Scan with BenQ DW-1655

TRT with the BenQ DW-1655

The ASUS DRW-20B1LT did a good job with this media from RiTek.

Quality Scan with BenQ DW-1655

TRT with the BenQ DW-1655

Here again, the ASUS DRW-20B1LT produces a very good quality burn, this time with our Taiyo Yuden media.

Quality Scan with BenQ DW-1655

TRT with the BenQ DW-1655

Our Memorex CDR Test disc burned with good results.

Writing Quality with Re-Writable discs:

Quality Scan with BenQ DW-1655

TRT with BenQ DW-1655

The results were good with our 32X Verbatim test media.

Summary:

CD-R and CD-RW writing quality was good with the ASUS DRW-20B1LT.

Now let’s head on to the next page where we will test DVD recordable performance….