I believe access to the cartridge is split evenly betweenthe 68K and the 32X with the 32X getting one access per 68K bus cycle. The SH-2s run at 3 times the clock of the 68K, but a 68K bus operation takes 4 cycles for a total of 12 SH-2 cycles for every 68K bus operation. If the SH-2 is only allowed one bus operation per 68K bus operation, it will take the SH-2 up to 12 cycles or so to access the cartridge bus. I believe it was said that DRAM access takes ~3 cycles. 12/3 = 4About the ram bus, i always thought it was full 32bit... I still think it is, else, why would the cartridge access be 3-4 times slower?
That said, even with a 16-bit bus, longword moves will still be more efficient than word or byte moves.