Instant. No OS. Whatever address word you put into the 6502 reset vector ($FFFC/$FFFD) it will happily jump to on power up or reset and start chugging right alo

Instant. No OS. Whatever address word you put into the 6502 reset vector ($FFFC/$FFFD) it will happily jump to on power up or reset and start chugging right along. The PPU (aka GPU) takes roughly 2 frames (33ms) to "warm up" and receive information, so, you want to wait for that by polling PPU_STATUS ($2002) with BIT and waiting for BVS twice when NMI fires. It is a good idea to disable decimal mode, disable audio IRQs, set the stack pointer, and zero the memory in a loop. Any booting and loading speed is entirely code dependent. https://wiki.nesdev.com/w/index.php/Init_code https://wiki.nesdev.com/w/index.php/Init_code