Real testing shows that there is no performance difference.
The first bit came from this thread at RizeNet. The K7 Master is intended for businesses and high end graphics designers, not everyday enthusiasts. This is very good reading from the guys over at real world tech. He's basically ranting about the ignorance of webmasters, manufacturers, and consumers. Despite the lack of consumer support for DVD Drives for anything other than watching movies, DVD drive manufacturers battle for the leading edge 16x DVD-ROM marketplace.