Today I burned my first Dual Layer disc, something I have long avoided due to the outrageous prices. But I decided to make that sacrifice for two such discs in order to backup the only RPGs I have for which I had no backup at all so far, those being "Xenosaga Ep1" and "Rogue Galaxy" (both un-backed-up because they require dual layer).
So I bought a couple of "Verbatim 4x DVD-R DL" with manufacturer ID "MKM 01RD30" which is apparently a good quality disc, from what I gathered by googling.
For my first test I then ripped the "Rogue Galaxy" iso from the original with DVD Decrypter (as I always do), then patched it first with Toxic DL patcher (a first for me) and then with the ESR patcher by ffgriever, after which I burned it to one of the discs mentioned above using ImgBurn.
My main purpose in wanting to make these backups was to allow me to play those games also on my v15 console, without wearing out the original discs, so my first test of the new-burned disc was to boot it on that unmodded v15, using FMCB+ESR.
To my great surprise this at first seemed to fail. The disc was recognized as being an ESR disc though, and ESR booted and went through the usual colour flashing, but the program did not seem to start like it should and the screen stayed black after the last colour flash.
In my very first test I gave up at that point, thinking that something had gone terribly wrong with the layer-break patching (as I'd never used that before), but I naturally went ahead with testing the disc on my modded v7 too, first with mod chip active (to see if my DMS4 could boot it, and then with modchip disabled booting FMCB and having it recognize the disc and launch ESR. (The very same operation that 'failed' on the v15.)
To my surprise both those very different tests on the v7 gave perfect results, booting the game with exactly the same speed and responses as when booting the original disc. So nothing was wrong with the ISO or the burn at all, as seen by DMS4 in the first v7 test and by FMCB+ESR in the second v7 test.
At this point I began to suspect that I had made some mistake in my earlier test on the v15, so now I repeated that test a few times, with variations (launching game from uLE with ESR preactivated and such tricks), but always with the same result. So I sat for a while thinking about the results of the last test, without turning off the console or TV, and after several minutes of sitting like that the console suddenly produced the normal startup screen of the game (where it asks what language you want to use).
So loading the program and data needed to display that screen, something my old and much used v7 managed to do in just a few seconds, took several minutes for a much newer, mint condition, v15 to perform.
And once I had 'exhausted' the data it had loaded for the first set of interactions I got another horribly long delay while it attempted to read some more from the disc.
The only sensible explanation for this is that the laser of my v15 is incapable of reading DVD-R DL discs reliably. It probably made several hundred retries for each sector, in order for it to take that long to display something so simple.
My theory is that the laser in my v15 (and thus probably in many slim consoles) simply can not be used reliably with a DVD-R DL disc, though the laser in my v7 (and thus probably in many fat consoles) has no problems at all with such a disc.
I'd appreciate it if others who have both a slim and a fat console (and some DVD-R DL disc, obviously) could repeat such comparative tests, so that we can get sufficient results for a valid conclusion (a single pair of tested consoles proves nothing).
Also, since my own failing console was an SCPH-77004 v15, I'd be very interested in DVD-R DL results from anyone with similar console models (mainly 750xx through 790xx), regardless of whether those tests involve ESR or modchip (as the laser is the same in either case).
Note that the results described above relate only to DVD-R DL discs, not to DVD+R DL discs, which I have not yet tried (don't have any at present). But results for such discs are also of interest. Just make sure to report exactly what disc type you used, preferably including manufaturer ID, as displayed by ImgBurn.
It is ironic that the main goal for which I wanted to make DL backups now seems impossible to attain, since the console I wanted it for can't read that disc with sufficient reliability.
Best regards: dlanor