Linux, Windows & MP4 playback CPU load

I recently installed Linux Mandrake 9 RC2, and it has good media player xine. It plays almost all possible formats and codecs. What surprised me is very low CPU usage when play DivX. First moment I thought that CPU usage meter is incorrect, but at DVD playback it shows real values about 40-45%. So, CPU load by playback is about average 3-5 % only. It goes for moments up to 8% when play DivX 5 with B frames. In Win I have 30-45 % with ffdshow and more with DivX 5.02 codec. There is no postprocessing (as I see) for now in xine, so I meusured without it in Win, however as I see it has no much influence to CPU load by me. System is KT266A board with 256 MB, Athlon 1200 underclocked to 1066 MHz currently. Very interesting, and I wait Win portal of xine...

It is propably not xine that is that fast, as I got about the same results with mplayer. The decoding is in both cases done by libavcodec (FFmpeg) which does a quite good job in both decoding and encoding MPEG-4 :D

If i remember correctly, part of the CPU load used for displaying (X11 stuff) is not taken into accound in the process CPU time but in X11 process. So the real value may be a bit higher.