I have had the same problem you have until half an hour ago, when finally after two weeks of struggle I decided to upgrade my 3500AG firmware to one of these RipLock Patches, Although I downloaded several of these patched firmware from TDB brothers site which I am grateful for this services they provided to us DVD Burner users, I decided to go with my drive original (stock) firmware with patch with RipLock (3500AG_2, 16 With RipLock Patched).
after successful flashing through Windows started ripping the same DVD Video which the drive was ripping at the rate of 3500K/S now the drive starts at 4500K/s reached speed of 9500K/s.
Although this is tremendous change of ripping speed but still far from desirable one not even reaching PCdoc speed which is 14000K/s. Many thanks to TDB Brothers, and you PCdoc and you q-T.
BTW: The drive still indentifies as ND-3500AG_2.16.