The only way to make the player use less cpu would be if it was able to bypass completely pulseaudio and gstreamer.
PulseAudio might be good for the desktop but for a portable device it's just way too much of a ressource hog. Adding to that the fact that the gstreamer backend is slower than the xine backend (at least on PC) that gives you a bad mix for a poor 600Mhz mobile cpu