Thats a new one on me
I have done lots of demos/games and I have found that you get far better speed results when you disable multi-tasking. The sonic demo that I did was only possible because I disabled multi-tasking and I used a lot of screen copying to create the parallax effects. With multi-tasking enabled it is jerko-vision!
However, I take on board what you have said regarding the blitter and will look into it.
On another note, I am seriously thinking of migrating to AMOS Pro simply because of the extra features and the ability to use the AMCAF extension. Maybe I will gain more speed using the AMCAF extension in AMOS Pro than I would by disabling multi-tasking in AMOS1.3.
Cheers, Kev G.