I had an interesting experience today and thought I would share. My sister gave me a copy of "They Live" on DVD as a gift. It's been unavailable on DVD for awhile. She found it at a video store that was going out of business. Anyway, the disc had some scratches on it from the wear and tear it took. I wanted to make a back-up and use that instead.
I ripped it with DVD Decrypter v3.2.1.0 on my Lite-On LTD163 DVD-ROM. The drive slowed down at 50% to 0.2x at the first part of the first VOB and then continued to 60% where it slowed down again to 0.1x. It retried 20 times to read the sector and then gave up. I have DVD Decrypter set to retry 20 times. I then tried the same thing with my Pioneer DVR-106D and it had the same behavior and couldn't get past the 60% mark and maxed out on retries. I was a little bummed but thought I would try my old Toshiba laptop which had a very early DVD-ROM drive in it. The laptop Toshiba was able to read it after 4 retries at the 60% mark of the VOB. I then decided to swap the Lite-On DVD-ROM for a Toshiba SD-M1712 I bought to use in a standalone DVD player. The drive was speed limited to 2x ripping, but it went through the VOB without a burp. Feeling in the scientific mode I then flashed the Toshiba with region free and speed limit removed firmware and it again ripped the DVD only dropping to 5-6x from 8x at the 50% and 60% mark. Just to make sure the DVD didn't change at all I repeated the process with my DVR-106D and it gave up at the same place as before.
I am impressed with the SD-M1712. I just checked and NewEgg has more of these drives in. They were hard to find there for awhile.
Jim