detail information

The specifications of this drive tell us that it should write both DVD+R and DVD-R discs at 16x. In this portion of the review we will measure the write time for various types of DVD-/+R discs. We will also focus on write quality and media compatibility.

DVD-Writing performance:

First, we shall take a look at the writing technology used for DVD+R and DVD-R writing.

16X DVD+R Writing speed:

The ASUS DRW-1604P uses Z-CLV, (Zone-Constant Linear Velocity) to write DVD+R at 16X.

16X DVD-R Writing speed:

The ASUS DRW-1604P also uses Z-CLV, (Zone-Constant Linear Velocity) to write DVD-R at 16X. Let us compare these to the write technologies used by some other drives:

The Mad Dog MD-16XDVD9 uses CAV (Constant Angular Velocity) to write to DVD+R and DVD-R discs at 16x. The dips in the graph are caused by the Active OPC technology, which improves burn quality.

The Memorex F16 uses CAV (Constant Angular Velocity) to write DVD+R at 16x.

Next we will test and measure the time for writing to DVD-R and DVD+R discs within Nero. We used Nero burning Rom to burn an ISO compilation containing 4483MB of data. We used the Disc-At-Once write method.

DVD+R test burn

DVD-R test burn

How does the ASUS DRW-1604P compare to other writers on the market? We have built a table to analyze these write times. Please reference below for our comparisons:

*Actual writing speed was 12X in these areas for the Pioneer A08.

The ASUS is one of the slowest 16x writers due to the Z-CLV (Zone-Constant Linear Velocity) writing technique.

A more important question is; how is the DVD±R/RW write quality of this drive? After all, you do want to be able to produce discs that are readable and useful. Let us find out now!

Write quality:

You should first take note that this is not a scientific and professional way to test the discs. But according to our testing done in the past, we would conclude that there is a clear link between the quality reported when scanning the disc and the playability of the disc in different devices. Also notice that different drives report different amounts of errors. K-Probe was designed to work with Lite-On DVD-Writers. So we recommend using a DVD-Writer from Lite-On. In these tests we use a Lite-On SOHW-1633S DVD-Writer, as already said; remember that scans done with a Lite-On DVD-ROM or Lite-On combo drive can't be compared with the results obtained with a Lite-On DVD-Writer. Also remember that different PI/PIF ECC sum settings along with different reading speeds in K-Probe will affect the result, we use these settings;  PI (Parity Inner) set to summarize 8 ECC blocks, PIF (Parity Inner Failueres) set to summarize 1 ECC block, reading speed: 4X CLV (Constant Linear Velocity). Setting the PI sum to 8 and the PIF sum to 1 will give a result that we may compare to the standards for DVD+R/RW and DVD-R/RW.

But what is a good scan? That is a discussion that we don't think will end soon. This is due to the fact that different drives report different amounts of errors, some players are more picky about media than others and many other factors. For comparison purposes we present you with a scan from two pressed DVD discs.

Please note that these 2 example scans below were performed with an older version of Kprobe. In this older version, PIF is mistakenly labelled as 'PO".

This scan shows the results from a pressed, Single Layer DVD-ROM disc (Baldurs Gate DVD-ROM).

This next scan shows the result from a pressed DVD-Video disk (Indiana Jones and the last crusade). Notice the error jump when shifting to the second layer (the error level actually drops from the end of the first layer to the beginning of the second layer).

If you read below you will see that both of the pressed DVD-discs are well within the standards.

Download the ECMA 267 Standard for DVD-ROM, the ECMA 337 Standard for DVD+R/RW and the ECMA 338 Standard for DVD-R/RW at http://www.ecma-international.org if you want to look at the standards for yourself. Here is some data from the ECMA standards (it is the same for DVD-ROM, DVD-R/RW and DVD+R/RW):

Random errors:

A row of an ECC Block that has at least 1 byte in error constitutes a PI error. In any 8
consecutive ECC Blocks the total number of PI errors before correction shall not exceed 280.

Here we see what a PI error is defined as a row in an ECC block having 1 byte or more containing errors. And that the sum of PI errors in 8 ECC blocks after each other should not exceed 280 PI errors.

But what is a row and what is an ECC block? Again we refer to the ECMA standards. We do not copy and paste everything but if interested look in the ECMA standards. A row is 182 bytes long where the last 10 bytes contain PI (Parity Inner) information. An ECC block is 208 rows long where the last 16 rows contain the PO (Parity Outer) information. This gives us a maximum possible PI error amount of 208 errors per block and for 8 blocks after each other this sum is of course 8 times higher giving a maximum possible amount of 1664 PI-8 errors. In practical use a disc with 1664 PI-8 errors is unreadable.

According to our tests the specified max PI-8 sum of 280 for good discs seems to be a good guideline, as some readers have problems reading discs when the PI-8 errors are over 300 and most players start to have problems when the PI-8 error level reaches 600 or more.

But what are the PIF errors that K-Probe reports? They are Parity Inner Failures, meaning errors left after PI correction. Only the ECMA 337 standard describes the Parity Inner Failures. So how is a Parity Inner Failure defined? Here is what the ECMA 337 states:

'If a row of an ECC Block as defined in 13.3 contains more than 5 erroneous bytes, the row is said to be 'PI-uncorrectable"."

In theory an ECC block may in the worst case have 208 PIF since every ECC block is 208 rows long. But the ECMA 337 standard goes further and specifies the max amount of accepted PI Failures (uncorrectable errors) allowed on a good disc:

'- In any ECC Block the number of PI-uncorrectable rows should not exceed 4."  

This means that when the PIF sum is set to 1 the maximum error value should not exceed 4. The theoretical maximum value for PIF is 208 errors.

But what makes a disc unreadable? A POF (Parity Outer Failure) error will make the disc unreadable, but K-Probe does not display the POF's.

Notice that there are other aspects such as disc reflectivity, jitter, tracking errors and so on that also will affect the readability of a DVD disc - but for this we do not have measuring equipment available.

Another detail to note is that we have scanned the discs at 4X CLV speed, by lowering the speed to 2X(DVD-R/RW)/2.4X(DVD+R/RW) or 1X the amount of reported errors may drop on some discs. We use the 4X CLV scan speed for all of our PI/PIF tests.

To see if there is a connection between the reported amount of errors and readability of the discs, we also include a transfer rate test reading curve from the NEC ND-3500A DVD-Writer. A small speed reduction near the end of the reading curve is still accepted on good discs, but serious reading problems or reading failures is a bad sign.

Easier explanation on how to read the test results.

Maybe this got too technical, and you are wondering what to look for in Kprobe reports?

Use this as a guideline for good discs:

PI(Parity Inner): No larger areas on the disc should exceed 280 PI-8 errors, do not worry too much about high single spikes that exceed 280. Lower error levels are always better.
PIF(Parity Inner Failures): No larger areas on the disc should exceed 4 PIF-1 errors, do not worry too much about high single spikes that exceed 4. Lower error levels are always better.

What about the reading curve? If the graph looks clean with no dips then the disc should be very good. A small slowdown near the end is acceptable.

DVD+R media compatibility and write quality:

Results here are ok except for the very end of the disc where there was a large slowdown in the reading curve.

Simply superb quality results here! Unfortunately the drive can only write to these 16x discs at 12x. It is interesting to note that a 16x burn only shaves 2-5 seconds off of the total burn time compared to a 12x burn on the ASUS DRW-1604P. The reason for this is due to the 16x writing technique utilizing an additional Zone (Zone-Constant Angular Velocity), which adds extra calibration time onto the total burn process.

Good quality results here with Ritek 16x DVD+R. Unfortunately the discs can only be written at 12x.

These 16x Fujifilm discs could only be written at 12x. Quality is very good as the PI/PIF is low and the reading curve is perfect!

Great results! This 8x media can be burned at 16x with good quality results.

Next to perfect results with this Prodisc 8x DVD+R. We can easily recommend this media for use in the ASUS DRW-1604P.

This 8x Ritek media was written at 12x! The PI/PIF results are ok and the reading curve is excellent.

This 8x Verbatim media was written at 12x! Excellent results in the Kprobe scan, but the reading curve had some trouble on the second half of the disc. Overall this is just an 'ok" result.

Beautiful! This 8x Memorex DVD+R media was written at 12x with superb results. Highly Recommended. It is also interesting to note that our burning software indicates that 16x writing is available for this media. However, multiple tests indicate that the ASUS will usually write to the discs at 12x, which is still very good since it is only 8x certified media.

The Kprobe scan looks great but the reading curve had some major trouble near the end of the disc. Not the best discs.

We also tested some other media types to determine their supported write speed. Some of these media types are not yet available on the market and will probably be supported at 12x/16x in a future firmware.

It is interesting to see that Maxell 8x DVD+R is supported at 12x, but Maxell 16x DVD+R is only supported at 12x!

DVD+RW media compatibility and write quality:

Very nice results here and we have no problems recommending these Ritek DVD+RW discs!

The ASUS DRW-1604P performed well with this media compared to our other drives. The reading curve is perfect.

Not the best we've seen with this Verbatim DVD+RW media, but still acceptable for DVD+RW results.

DVD+R/RW Performance Summary: The ASUS DRW-1604P uses a Z-CLV (Zone-Constant Angular Velocity) technique to write DVD+R at 16x. Z-CLV is slower compared to the CAV (Constant Angular Velocity) & P-CAV (Partial-Constant Angular Velocity) techniques that are used by the competition. We obtained mixed results when testing the DVD+R media compatibility of the ASUS DRW-1604P. On the one hand, it supports writing to some 8x discs at 12x and even Taiyo Yuden 8x DVD+R at 16x, which is very positive. On the other hand, it only writes to some 16x certified discs at 12x maximum. What about quality? The ASUS DRW-1604P impressed us with the writing quality results that we measured. It can write very well to a wide range of DVD+R & DVD+RW discs.

Head on to next page and read about DVD-R/RW compatibility and write quality...