Phenomenal test of DVDRW media

[pepst]

Dr. Gough Lui did not disappoint again and prepared what is certainly the most detailed, thorough, and laborious test of DVD RW media ever conducted. He tested the resistance of RW media to repeated rewrites, and the test yielded a few surprises.

I highly recommend reading it; it is an incredible piece of work:

Part 1: https://goughlui.com/2026/03/07/test...cma-standards/

Part 2: https://goughlui.com/2026/03/07/test...ology-results/

[huh22]

A very interesting article and tests. Even though I didnt understand some of the highly technical descriptions, I found the article to be informative.
Do you know if anyone has done any similar tests on CD-RWs?

[pepst]

Napisany przez huh22

Do you know if anyone has done any similar tests on CD-RWs?

I suppose we'll see something like that in the future.

[pepst]

There's a second part to the test; once again, I can't imagine (or rather, I can) just how much time and effort all of this must have taken.

https://goughlui.com/2026/08/23/test...he-contenders/
https://goughlui.com/2026/08/23/test...failure-modes/
https://goughlui.com/2026/08/23/test...a-dying-drive/

[huh22]

A fascinating collection, so far I have only read the first article, I wont have time for the second one today.
That reminded me that I have an Imation DVD-RW 4x lying around on my desk, but it looks a little different from the one in the article, and Media Type ID is OPTODISCW004. I also have an Imation DVD+RW 8x here, thats the Philips RW8-000. Ill read the next part tomorrow.

[misiozol]

Very nice, kudos

[huh22]

I read the second part and am a little surprised by how many new discs have degraded since then. Only two discs survived the entire cycle without any read errors. Ive seen these black spots in the recording layer before, this degradation occurred after far fewer burns than described here, and it was back when these discs were commonly sold, so they were relatively new. Its hard to say what caused it, maybe some kind of technological bug, an unfortunate combination of materials, or something like that.

[huh22]

I read the third article about DVD-RAM, the test sample wasnt very large, but some conclusions can be drawn.
Back then, in those -glory days-, I believed (based on technical articles at the time) that DVD-RAM was truly a suitable medium for backups. I backed up my accounting data on Panasonic Japan discs, and when those became unavailable on the market, I switched to Verbatim.
The switch to Verbatim was a major drop in quality, I remember one case where the layers of a new disc completely peeled apart, causing the disc to fall apart.
Unfortunately, backing up a large number of files was unbearably slow, so after a while I abandoned this technology entirely.
Now I see that, despite the claimed huge number of write cycles, it wasnt dramatically better than DVD+-RW, and the claimed advantages were, for the most part, just marketing hype when it came to long-term archiving.

[pepst]

What shocked me the most in the test? The poor - even disastrous -;results of most Japanese media. I was immensely disappointed that many of the tested media showed strong signs of DVD rot. Sure, most of the media is over 20 years old, but I did not expect them to ultimately prove more problematic than most cheap, single-use +-R media. I would be interested to know the cause - whether it is due to an inherent tendency of the rewritable layer to break down, or whether it is caused by some flawed, ill-conceived, or improperly executed manufacturing step, or perhaps an interaction between the recording/reflective layer and the adhesive bonding the two halves of the disc. Alternatively, given that these discs are by far the oldest among those tested (2002 - 2003), are we reaching the age-related limits of disc durability, and will we see the same issues in a few years with younger discs that have been problem-free so far?


On the other hand, I was pleasantly surprised that:

- One of the best test results was achieved by what was once considered the most run-of-the-mill medium possible: the Imation DVD+RW from Moser Baer.

- despite a large number of errors right from the start, the DVD+RWs from Infodisc - which were once widely disparaged and considered among the worst discs on the market - also showed unexpected resilience to repeated rewriting over the long term.

The Philips disc (actually produced by Philips OM&T in the Netherlands!) has a very high error rate, apparently due to problematic and poorly optimized firmware compatibility. Still, the quality is not bad; with better initial write quality, the recording layer would likely have withstood even double the number of writes, which is not bad at all compared to Japanese media.

[huh22]

It's hard to say what caused the degradation of the recording layer, I would think it might be because the technology was new, it was Japanese media rated at 2x, but the table also includes the TDK 2x DVD-RW TDK502sakuM3 (TW) with no read errors. In contrast, theres a Memorex 8x with errors after 100 cycles and a Sony 6x with errors after 200 cycles (all Ritek), and the MID Philips didnt show impressive results either. The result for the TDK 4x CMC MAG is a surprise to me.
The results are very much like a lottery.
I have a few RW discs lying around on my desk: Imation -RW 4x MBI01RWG 20, Imation -RW 4x OPTODISCW004, Imation +RW 8x PHILIPS-RW8-000, Verbatim +RW 8x MKM-A03-000, Verbatim +RW 4x MKM-A02-000, Philips +RW 8x, RICOHJPN-W21-001. I havent checked them yet to see if they have any spots (and Im not sure if Id need a microscope). These discs are quite worn, especially mechanically (lots of scratches), so I didnt even run a readability test. The damage isnt caused by the number of rewrites, I definitely havent done that many.
But I also have a Panasonic 2-5x M01J5006 DVD-RAM (Japanese, I assume) lying also here, its quite dirty and dusty, but after washing and drying it, it looks to be in good condition with only a few scratches. The folders on it date back to 2011 (15 years ago), and about 3 GB of space has been used. A surface test in Nero CD-DVD Speed showed 0.3% damaged areas and 0.3% unreadable areas. Hmm, I expected it to be fully readable :-)
But some of the scratches might have caused this, even though there arent many of them.

[huh22]

Update:
I was looking at it yesterday and noticed that theres also a black spot on this DVD-RAM. Its right at the edge of the disc, so it didnt affect the test because there are 3 GB of data recorded on it. Unfortunately, I dont have a good camera with a macro mode, but a friend of mine used to have a microscope, maybe we could take some better photos with that.

[misiozol]

Yah that is typical de-lamination of layers. Somewhere there is photo of my BDs, and one CD that was i think literally eaten by some microbes with marks of eating on it.

[huh22]

I managed to borrow a school microscope, so here are some photos of a spot on a DVD-RAM. Unfortunately, the microscope didn't have very high magnification.

[misiozol]

Delamination 100%