Minecraft wiki entry for Hopper, associated text: In Java Edition the checks done by a hopper while pulling generally require less processing than the checks done by a hopper attempting collection. Therefore, a chain of hoppers topped with storage containers rather than air/solid blocks has better performance (measured as milliseconds of processing per tick) and lower potential for processing lag. [4] The performance improvement achieved is correlated with the the number of storage slots the container has. Placing composters (with no storage slots but still with custom output logic) on top of hoppers provide the greatest efficiency, while double chests actually degrade performance, even when sharing each double chest across two hoppers.[4] In Bedrock Edition a chain of hoppers with air or non-container blocks on top has better performance than a chain of hoppers topped by container blocks.[5] This may be because, even though hoppers with containers on top do not check for items, they do check for hopper-minecarts and chest-minecarts to pull from, and that involves scanning the chunk entity list.[6]