Frame Rules, Subpixels, and Why One Frame Actually Matters

Why I call myself Frameskip... and what happens inside an old console in a sixtieth of a second.

People new to speedrunning sometimes wonder why runners lose their minds over a single frame. On an old console running at sixty frames a second, one frame isn't just a blink of an eye... it's the heartbeat of the whole game.

Sixty Heartbeats a Second

On classic 8-bit and 16-bit consoles, the game basically wakes up sixty times every second to check your controller, move your character, and draw the screen. That's roughly 16.6 milliseconds per frame.

If you hit jump one frame late, you don't just lose 16 milliseconds. You might miss a cycle check, catch a door right as it locks, or miss a frame rule that makes you wait another third of a second before the next stage even starts loading.

Subpixels and Fighting Lag

Even when your character looks like they're standing still on the screen, the game's memory is tracking tiny fractions of a pixel... subpixels... right under the hood. Carry the right subpixel speed into a jump and you clear the gap; miss it and you clip the ledge.

And then there's lag. Put too many enemies or explosions on screen at once and the console's processor chokes, dropping a frame. Half the craft of routing an old game is figuring out where to look, or which enemy to despawn, so the hardware never slows down.