@weirdami
I believe the default rendering uses the Amiga blitter to speed the text display. Obviously, the Amiga blitter won't do anything on the graphics boards display. An AmigaBlitter=TRUE tooltype would be more logical today. RTG=TRUE would have been better than PICASSO=TRUE too.
@all
I believe there is a setting to select simple refresh over smart refresh which will speed screen updating up noticeably with a gfx card. Always set simple refresh on gfx board screens for the fastest screen updates.