Couriersud, do you have any ideas? The path through MAME should be identical to baseline, and Wine ddraw is definitely not a magic fast box - without OpenGL it's usually about 20% slower than real Windows on the same h/w.
The poster gave only little detail. No mame commandline, no /etc/directfbrc, no mame verbose output, no stderr output running mame to see what directfb is complaining about, no dfbinfo
from the source
if we're using the memory buffer, draw offscreen first and then copy
That's in fact a software renderer. As is the other case where it uses the software renderer to draw directly to the window surface - just overdrawing this (NO_DEST_READ=1). Depending on the blend mode and color/alpha set this may cause a real difference.
I think the base package posted here for such issues should be
b) mame commandline
c) game.cfg (are we talking artwork?)
d) mame -v output incl. stderr
f) dfbinfo output
That is a lot, but issues like that tend to be complex.