playback of my encode uses more CPU than normal

[pinko]

I just encoded my first divx movie, playback is fine except that it seems to use more cpu power to playback than other movies.

I usually have post processing at 50%, and this has never caused a problem on my system, but for my encoded movie, i have to turn post processing down to the minimum level in order to maintain synch between audio and video.

if the bitrate, framerate, resolution and all that stuff are the same, what would cause one movie to need more CPU power than another?

Some details:
Movie is 740kbps, 640x480 (pan&scan) 23.976 fps.
From a telecined dvd source, (i used inverse telecine and a deinterlace filter, along with a couple other filters in virtualdub.)

Computer is a Athlon 700Mhz, 384mb ram, 7200rpm hard drive, 32mb Geforce video card.

any ideas?
thanks in advance.

[khp]

How was the movie encoded ?.

With Divx5, playback becomes much more cpu intensive, when the movie was encoded using any of the three Mpeg-4 options.