I demand that Nicolas Huillard may or may not have written...
[snip]
DFB must be way lighter than X. In my case, it is nearly 80MB RAM less (counting X + Xine - softdevice). CPU utilization depends on hardware acceleration, WTR MPEG2. Nothing should impact CPU in DFB per se.
Something else to try: GTK+ (fb port) with gxine. I'd be interested in knowing how well this works and in any patches for gxine which are needed to make this work (if it doesn't already).