detail information

The specifications of this drive tell us that it should write DVD+R discs at 8x and DVD-R discs at 8X speed. In this part we will measure the write time for various types of DVD+/-R(W) discs. We do also focus on write quality and media compatibility.

DVD-Writing performance:

We will start with taking a look at the writing strategy used and compare it to other drives;

The above image shows an 8x DVD+R disc written at 8x.

The above image shows an 8x DVD-R disc written at 8x. Some 4x DVD+R disc will also be written at 8x using the two zoned Z-CLV strategy shown above.

The MSI DR8-A2 uses P-CAV (Partial-Constant Angular Velocity) to write 8x DVD+R media at 8x, but 8x DVD-R media as well as some 4x media written at 8x is written using Z-CLV, (Zone-Constant Linear Velocity) technology. This means it's among the faster drives for writing 8x DVD+R discs at 8x and uses just over 8 minutes to write the disc. But for DVD-R it's quite slow since it uses a two zoned CLV writing mode where the first zone is written at slow 4x speed, total time used to write a DVD-R disc at 8x is close to 10 minutes making it one of the slower 8x drives for DVD-R media. Comparisons with two other drives are found below.

The NEC ND-2500A uses Z-CLV, (Zone-Constant Linear Velocity). The first zone from 0-0,8Gb is done at 4x speed, the next zone from 0,8Gb to 2,2Gb is done at 6x speed and the last zone from 2,2Gb to 4,4Gb is done at 8x. This gives an average speed of 6.80x. The speed is the same for both DVD-R and DVD+R discs.

The Plextor PX-708A also uses Z-CLV, (Zone-Constant Linear Velocity). The first zone from 0-0,7Gb is done at 6x speed; the next zone from 0,7Gb to 4,4Gb is done at 8x speed. This gives an average speed of 7.69x.

Let us see how long time it needs to create a disc with Nero. We used Nero burning Rom to set up a new UDF/ISO compilation containing 4483Mb of data, and started the write process. We used the Disc-At-Once write method.

DVD+R

DVD-R

As we could see the MSI DR8-A2 used a bit over 8 minutes for the DVD+R disc and close to 10 minutes for the DVD-R disc, to see how this compares to other drives, look at the comparison table below.

As we could see the drive is among the faster drives for writing DVD+R at 8x, but among the slower drives for writing DVD-R at 8x. This is of course due to the different writing techniques it uses. Now it's time to take a look at the writing quality of the MSI DR8-A2.

Write quality:

You should first notice that this is not a scientific and professional way to test the discs. But according to our testing done in recent months, 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 this test we use a Lite-On SOHW-832S 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/PO 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, as different drives report different amount of errors, some players is more picky about media than others, and so on. But as a comparison we present you with a scan from two pressed DVD discs:

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

This 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 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 (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 is over 300 and most players starts 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 are what 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.

And another 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 scanned at 4X CLV due to lower speeds taking to much time.

To see if there is a connection between the reported amount of errors and readability of the discs we also include the reading curve from a JLMS XJ-HD165H DVD-ROM that is using a modified firmware and thus tries to read the discs at full 16x speed. Reading the discs at full 16x speed could almost be considered a 'torture" test and most discs will slow down near the end. Only the best of the best discs will be able to get a perfect reading curve, so our limit for good discs will be: A speed drop at the end is accepted, but the reading speed should not drop below 6x for longer periods (small dips below 6x is accepted).

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.
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.

And as always; lower is better ;)

And look at the reading curve, some slowdowns is expected with most media, but the reading speed should not drop below 6x for longer periods (small dips below 6x is accepted).

DVD+R media compatibility and write quality:

None of the newer/unknown discs were supported at more than 4x '? but we hope a future firmware fix that.

Head on to next page and read about DVD-R compatibility and write quality as well as DVD+/-RW writing quality and speed...

CD-R/RW Writing performance

DVD-R Quality and DVDRW performance