Originally Posted by Heretical_One
The system doesn't have enough bandwidth to render the worst case scenario unless 2 complete sets of BG tiles are loaded at the start of rendering. It also explains why the left tile in Mode 2/4 is not offset smile

I'm having a hard time wrapping my brain around what you mean by that. What exactly is "double buffered"--the tile pattern data? And how does that help with bandwidth? What is the "worst case scenario", and what happens if it occurs on more than one scanline, or even on every scanline?