It sort-of did have fast RAM for video! The chips used could do 2e6 bytes/second, or thereabouts, of which the CPU could demand just ~1e6 (or near enough), at p

It sort-of did have fast RAM for video! The chips used could do 2e6 bytes/second, or thereabouts, of which the CPU could demand just ~1e6 (or near enough), at predictable regular intervals. The remainder is entirely free for the video system! (This was a very common arrangement for the 6502, as it has predictable data bus accesses.) I'm not especially familiar with the Apple II's graphics capabilities, but it sounds like all its various modes need ~1 byte/microsecond for the visible period, so this would work out.