detail information

The specifications of this drive tells us that is should write both DVD-R and DVD+R discs at 4X speed. In this part we will measure the write time for various types of DVD-/+R discs. We do also focus on write quality and media compatibility.

DVD-Writing performance:

In this test we will measure the time for writing to both DVD-R and DVD+R discs. 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

Out from these screenshots we could see that the LG GSA-4040B wrote the DVD+R in 14 minutes and 44 seconds, and the DVD-R in 14 minutes and 56 seconds. How this compares to other drives may bee seen in the table below:

Out from this table we could see that the drive is about as fast as Sanyo CRD-BPDV2. Basically it won't win a price for being the fastest 4X writer. But write speed is not everything, so let us look at media compatibility and write quality below.

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 the last two months we could 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 reports 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 LDW-411S 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/PO (Parity Inner/Parity Outer) Sum: 8 ECC, reading speed: 4X CLV (Constant Linear Velocity).

But what is a good scan? That is a discussion that we don't think will end soon as different drives reports 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 that only the first layer is scanned.

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

Download the ECMA 267 Standard from http://www.ecma-international.org if you want to look at the standard for yourself. Here is some data from the ECMA 267 standard for pressed DVD discs:

13.4.2 Random errors

A row of an ECC Block (see clause 18) that has at least 1 byte in error constitutes a PI error. In any 8consecutive 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 267 standard. We do not copy and paste everything but if interested look at point 18 in the ECMA 267 standard. 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 contains 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 errors. In practical use a disc with 1664 PI errors is unreadable.

Although this standard is for pressed DVD-ROM's we have found it to be a good guideline for recordable DVD media as well. And according to our test the specified max PI sum of 280 for good discs seems to be a good guideline, as some readers have problems reading discs when the PI failures is over 300 and most players starts to have problems when the PI failures reaches 600 or more.

For PO errors we have yet to find any standards describing how they are defined and how many PO errors that is acceptable for a good disc. And thus we do not focus on the PO errors in this test, but keep in mind that lower is always better.

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.

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 seems to be pretty easy affected by the quality of a written disc.

DVD+R media compatibility and write quality:

For this Taiyo Yuden DVD+R media it seems like the drive is not using the correct write strategy and thus leading to a less than excellent result. Both the reading curve and the K-probe scan show problems but the K-probe scans shows most problems in the beginning of the disc while the reading curve shows problem at the end, this may be because of the higher reading speed of the JLMS XJ-HD165H at the end.

With these discs the result is pretty acceptable, but we could still see some tiny bumps in the reading curve where the error level is highest at the disc. But these discs should not cause you any trouble.

Again the drive must use wrong write strategy to write as these discs works considerably better on most other DVD-Writers. Disappointing, but true as both K-Probe and the reading curve shows the same problem. Avoid discs with RICOHJPNR01 as the media code if you have an LG GSA-4040B writer.

Again the K-Probe scan and the reading curve show the same thing; avoid these discs as much as possible. The result is really bad. Just to have that mentioned as well: First time we tried writing this disc type on the LG GSA-4040B the drive failed while writing.

DVD-R media compatibility and write quality:

Now, this was something else! Both the K-Probe scan and the reading curve agree: The produced result with these discs is simply outstanding! The produced result is even better than for the original pressed discs according to K-Probe. Highly recommended discs for this drive.

Again a disc type that is about middle of the tree when written by the LG GSA-4040B. The reading curve shows some problems at the end, maybe this have a connection with the increased amount of PO errors at the end of the disc.

There is no doubt this time either; there is a clear connection between the K-probe scan and the readability of a disc, the amount of errors increased at the end causing a slight slowdown in the reading curve. But all in all the result is pretty good. To bad these disc works at 2x only.

Again we could see that both K-Probe and the reading curve show most problems at the same place. Actually we expected that the result of these discs would better.

Although the K-probe scan show this disc to be of acceptable quality the reading curve shows that there is some reading problems at the end. Notice that we scanned at CLV in K-probe while the transfer rate test curve is CAV, and higher reading speed requires better quality. There may also be other problems such as jitter or tracking errors that we are unable to measure with our equipment. It's also limited to 2X writing on these discs as well.

Here we could see that both the K-Probe scan and the reading curve agree, there are a few problems at the end. Actually the result with this disc is surprisingly good, as princo is known to be among the lowest quality discs available.

There is only one reason why we include a second type of princo discs; to show the difference in quality of princo discs. These discs have a bit different ADIP and serial number, and according to our test results the quality of these discs is much lower than the other princo type we have. And we could see that the amount of errors is higher at the end. Actually the disc is so bad at the end that it's unreadable as the reading curve shows.

This is one of the few results where the K-Probe scan and the reading curve do not completely agree, the K-Probe scan shows most problems at the beginning while the reading curve shows most problems at the end. But they both agree on that these discs are not the best. The reading curve may be affected by other quality problems such as jitter or tracking errors that K-Probe do not measure. These discs are only supported at 2X writing.

As in most cases the reading curve and the K-Probe again agrees and shows problems at the same place. These discs also failed to work at 4X and are limited to 2X writing only.

That was all we had available for this time and we actually got a bit surprised by the results ourselves, and had expected better results, especially with Taiyo Yuden and Ricoh DVD+R media.

Notice that we had limited amount of media available due to limited amount of media available in Norwegian stores. Discs that we would like to include in our reviews: Maxell, pioneer, prodisc, and optodisc 4X certified DVD media. But currently discs from these manufacturers are not found in Norway.

As we could see the LG GSA-4040B do not have the best media compatibility available as only the most known manufacturers + the princo and bulkpaq discs worked at 4X. It's disappointing to see that it even fails with the CMC Magnetics discs and only wrote these at 2x, as CMC magnetics can't be called an unknown manufacturer.

This concludes our DVD-writing tests so head on to next page and read about the packet writing performance of this drive…