bad performance on playing video

[ad]

I use Xine to play VCD, DVD and other video files, the audio performance
is good, but the performance is awful, lots of lag. My CPU is PIII 1G,
764Mb ram, and AGP card with 4Mb ram. So I don't think my hardware is not
powerful enough to play video.
I set up MTRR support. What else should I do to increase the video
performance?