I have just stupid. Or are just tired. I do not know. Anyway, thanks! By carefully reading I remembered the option "destroy sprites" when no longer present in the game and "creates sprites" when they enter the playing area. The next test has released plenty of memory, and now the game goes much faster.
Initially I tried to follow the choice "make visible or invisible" but endeavored memory was still too much.
Thanks again. You are a breath of fresh air!