[DVD-o-matic] conversion speeds?

Did anyone have the same experience: I was checking the trim feature yesterday with specially made test footage - an MP4 file with frame accurate numbers counting from 1 to 300, white numbers on black background. On my sandybridge notebook, it converted at around 4fps, no special processing (1998*1080 in, 1998*1080 out). With real word footage (but also a large number of black frames at the beginning), I only get around 1fps conversion speed, sometimes even below that. Is the J2k compression speed depending on content complexity or target datarate? I could see in the log that the MXF frame write intervals reflected these different conversion speeds perfectly. Both files on local disc. Will need to do some more testing. I have a large project with a lot of partial/trimmed conversions ahead. Carl - when using encode servers, I guess the main dvd-o-matic server will send uncompressed still images to the remote J2k encode servers? That's why a Gigabit network is beneficial? - Carsten