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 Angular Velocity) to write DVD+R at 16X.

16X DVD-R Writing speed:

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

The NEC ND-3540A 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 Toshiba SD-R5372 also uses CAV (Constant Angular Velocity) to write DVD+R at 16x.

How does this drive compare to other writers on the market? We have built a table to analyze these write times. Please reference below for our comparisons:

*1 - Actual writing speed was max 14x due to USB-Bridge limitations.
*2 - Actual writing speed was max 13x due to USB-Bridge limitations.

The ASUS 1608P 16x writing speed is about average compared to other drives.

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-Video disc (Ronin).

This next scan shows the result from a pressed DVD-Video disk (Lord of the Rings, Return of the King). 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:

Very good writing quality on this 16x CMC DVD+R media. We are disappointed to find that it is only supported at 12x maximum writing speed.

Very good quality results here with Verbatim 16x DVD+R. Highly recommended.

16x DVD+R from Optodisc could only be written at 12x maximum. We can see very nice quality results here, but ASUS definitely needs to fix the support and enable proper 16x writing!

Spectacular results with this 8x Memorex media manufactured by Moser Baer. We can easily recommend these discs.

The Kprobe results look excellent. Unfortunately the reading curve had some problems, which could indicate some quality problems. The writing speed also dropped to 12x near the end of the burn. Overall it appears to be an okay result.

This high quality 8x DVD+R made by Taiyo Yuden was written at 12x with good results. We have seen even better results on this media at higher speeds on other DVD writers.

This is crap media that produced horrid results. We tried writing another disc and the burn process failed. Avoid this media!

Our testing reported elevated PI levels in the Kprobe graph, but they are still within the acceptable guideline. The PIF levels and the reading curve look good.

This 8x Verbatim media was written at 12x! The Kprobe scan as well as the reading curve both show ok results.

Very nice! This 8x Memorex DVD+R media was written at 12x with good results. Highly Recommended media for this burner.

Results look very good on Optodisc 8x DVD+R.

Acceptable results here on this 4x CompUSA DVD+R media. The reading trouble at the end of the transfer rate graph could indicate some small quality problems near the end of the disc.

DVD+RW media compatibility and write quality:

Scary results with this 8x Ritek DVD+RW burned at 3x. ASUS really needs to fix the support for these discs!

There is a small block of reported PI errors that reached up into the 250 range, but other than that the result is pretty good. The reading curve is perfect.

Good results on Verbatim 4x DVD+RW, written at 4x.

DVD+R/RW Performance Summary: The ASUS DRW-1608P displayed excellent writing quality on a range of DVD+R/RW media. ASUS needs to fix the media support to enable proper support for more 16x media such as RICOH, Ritek, CMC and OPTODISC. The 8x DVD+RW media support is also lacking as we were unable to write either Verbatim or Ritek 8x DVD+RW at the proper speed. A few 8x DVD+R media (Mitsubishi, Taiyo Yuden, CMC) were able to be written at 12x with good results, which is a big plus. The overall writing quality is very good but the support for 16x media and 8x DVD+RW media is lackluster.

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