FInally getting on average 6.6x DVD burning out of my media/drive combination after using a Windows LiveCD to upgrade the firmware on my drive.
While 6.6x may sound slow given that 16x drives and 8x media are so cheap, you have to realize that no 16x, or affordable 8x DVD recorder writes with a constant linear velocity — and they certainly don’t advertise anything other then the max on the side of the box 
Your typical 16x DVD recorder writes at different speeds in varying ‘zones’ around the surface of the media — slow early on in the center, and maybe at it’s max speed towards the outter edge.
So even if you came back from the future with perfect 32x media and hacked your burner to recognize it, you’d still write the inner tracks at closer to 8x.
