I just tried writing a DVD video at 16x, approx 4.35 GB. Setup took about 2 seconds, lead-in took 50 seconds, lead out took 10 seconds, and actual data took about 5 minutes. Total time, 6:02.
5 minutes to write the data would calculate to about 15,200 KB/sec, but Nero was reporting a speed of 22,160 KB/s.
So according to my calculations, either Nero reported the wrong speed, or there is an extra 2 gigs of data written to the disc, or a third possibility is that the writer spends almost 1.5 minutes not actually writing data.
Edited: to correct lead-out time
5 minutes to write the data would calculate to about 15,200 KB/sec, but Nero was reporting a speed of 22,160 KB/s.
So according to my calculations, either Nero reported the wrong speed, or there is an extra 2 gigs of data written to the disc, or a third possibility is that the writer spends almost 1.5 minutes not actually writing data.
Edited: to correct lead-out time