I guess it depends on your mainboard/BIOS. With my nForce board I can enable/disable DMA on the nVidia SATA channels in BIOS. Whether this has any effect in Windows, I don't know. When I disable DMA on my SATA burner channel in BIOS, I can still burn at full speed. It should be clear whether your BIOS DMA setting refers to the PATA or SATA channels. Not using DVDFab, so can't comment on that. If you can burn DVD's at 16X speed, there shouldn't be any cause for concern.