Long burn time with Nero



I have Nero 8 installed and am using Nero Vision to burn dvd’s. I am burning TV progs that I have downloaded but it takes 3 - 5 hours to burn a 1 hour episode.

when I was burning with Nero 7 it would take about an hour or so to burn a 2 hour film. Now everything seems screwed up since I went to Nero 8.

Admittedly, the stuff I am downloading comes from a UK site and much of it is in PAL format with some NTSC. I am burning it to NTSC. Is this whats screwing up the time?

Am I doing this right?
Should I convert it to NTSC somehow before I burn it?

All help gratefully received.