I recently purchased an external USB 2.0 DVD burner (Phantom). I am new to
burning DVDs. I am using k3b to burn a 4GB Knoppix Live DVD iso image from
the hard disk right now. I find that I am burning at about 980 KB/s
(~0.7x). Is this normal ? I find that the buffer status bar indicates "no
info". When I burn CDs on my internal CD burner on the same machine with
k3b, the buffer is usually 98-100% full. I get the impression that I have
setting somewhere or some kernel option that I have not turned on.

This is a Debian Sarge (stable) system with up to date packages.