Hey everyone!

If your Scratch project is running slowly because you're using large lists, here are some tips to speed things up:

Limit List Updates: Only update lists when absolutely necessary. Use variables for frequently accessed data instead.

Use Broadcasts: If you're working with multiple sprites, trigger updates with broadcasts instead of checking conditions every frame.

Clone Efficiency: Be careful with excessive cloning of sprites that use lists. If possible, use one sprite and switch costumes for performance.

Preload Data: If you're displaying a lot of items from a list (e.g., a leaderboard), preload the data into a variable instead of fetching from the list every frame.

Custom Blocks: Use custom blocks with ‘Run without screen refresh’ to process lists faster, especially when sorting or modifying data.

Hope this helped, Happy ScratchTober!

Nice information!
But unfortunately, Scratch Team thinks that this will clog up the discussion forum, I don't know.

I wish this was stickied.

I was wondering why my enemy clones (who have two lists inside them) were lagging the game when I added a custom block with a “run without screen refresh” to their code.

Although i don't suffer from high-cpu usage, i suffer FROM MEMORY USAGE.

i think the lists thing is especially relevant here: https://scratch.mit.edu/projects/1218001801/editor/

(unless i solve it before you see it)

Hide the list, otherwise Scratch copies the entire list to the display in every frame when something in it has changed