This will vary depending on many factors, such as the capabilities of your drive, internal bus speeds, and DVDFab settings. Compressing the content (DVD-9 to DVD-5) will make it seem slower. The quality of the pressing and type of reflective layer on the disc also matter, sometimes greatly. My drive for instance will read most discs at a peak speed of 10.5 MB/s, which is around 8X. Some originals though max out at 5 MB/s, even new ones. The speed will also vary depending on the position being read, with the highest speeds near the end of single layer discs and near the layer break on DLs. In drive specs, the DVD-ROM read speed is not necessarily the DVD-Video read speed, and not all manufaturers provide the DVD-Video read speed (which is usually slower) so it is hard to know what to expect.
