60fps encoding speed ok for a core2duo 2.00GHz?

I’m actually testing dvd-fab platinum on my new notebook, especially the dvd-to-mobile ipod feature.
The notebook runs with Windows XP SP2 and has an Intel Core2Duo clocked each core at 2.00GHz, 1GB DDR2 RAM and a fast enought 5400 rpm hdd.
To test the speed I copied a dvd to harddisc and used then these settings for encoding:
dvd-to-moblie: ipod
profile: mpeg4 one pass encoding
bitrate video: 768
bitrate audio: 128

Result: max. 60 fps encoding
Can this be normal? total cpu-usage isn’t more than 50%! Seems to be a bit to slow for a brand new cpu anno 2007?

This is not out of line with my results (P4HT 3.2GHz, 2GBDDR2, 5400 RPM). The screen size seems to be the variable that most effects conversion speed for me, and some profiles are faster than others (one, I think it is the Generic Xvid+audiocopy) runs at 90+ fps from a HDD folder source, 320x240 size and a correspondingly lower video bitrate). It might help a little to have the source and target drives on different IDE channels (I have one on IDE, the other USB).

so if it isn’t out of line, the question is why doesn’t use the mpeg4 encoder the whole possible cpu?