Have you tried to use E-UAE in fullscreen? As Richard explained in a
previous post:
On most platforms I would expect windowed-mode to be slightly slower than
full-screen - if only for the reason that UAE gets the display to itself in
full-screen mode and so there's less clipping, layering, or whatever for the
graphics system to take care of.
On OS X, the difference is substantial, however. This is because, in windowed
mode, the rendering has to go through the Quartz compositing layer.
