Note that when backing up DVD movies, you are dealing with read/rip speed, and transcoding speed. A fast reader may knock 3 to 4 minutes off the rip time. The average DVD writer should be able to read a DL movie in about 12 min. Depending on the level of compression and the speed of your computer, transcoding may add another 50 minutes to the total processing time.
Under IDEAL conditions, you can expect to reduce the total processing time by 4 minutes with a fast DVD reader.