CompuServe Messages

Lores 5-planes is also in contention, altho only around 14% in 320×200 mode. Anything over 4-planes in lores mode, or over 2-planes in hires mode, takes away potential cpu->chipram access slots, which are only available on every other 280ns chipram cycle to begin with. And anything over _0_ planes starts to take away potential blitter cycles! In lores 16-color overscan, around 35% of blitter slots are unavailable. Here's the the slot allocation for every one lores dot, or two hires dots: 4 6 2 3 5 1 lores plane usage |___|___|___|___|___|___|___|___| 280ns chipram slots 4 2 3 1 4 2 3 1 hires plane usage x x x x x=cpu slots From the above, you can see that using 3 hires planes takes away 1/2 of the cpu slots, and 2/3 of the blitter slots… during active video DMA time (thus using overscan makes things worse). best – kev