Direct answer
A hopper clock repeatedly moves items to generate redstone pulses. Its cost depends on the number of clocks, surrounding inventory checks and attached machines.
How to check it
- Locate the actively ticking hopper clocks and test one representative contraption while recording pulses and a spark sample. Pause unused clocks to see whether MSPT changes.
- Record the original configuration or test conditions, capture a profile or a repeatable observation, and identify the affected world or player group.
- Make the measurement under the same player count and workload you will later use to verify the change.
What to change
If possible, turn off clocks when nobody needs them, use fewer always-loaded devices and check the downstream machine for unnecessary block updates. Do not replace clocks with command blocks without measuring the replacement.
Confirm clock period, attached farms and shutdown/restart behavior before deploying a redesign.
Software and version notes
Check the active version and generated configuration before copying paths or values. Different forks and mod loaders may implement this behavior differently.
This article is written for Paper / compatible servers. Configuration keys and defaults can move between versions. The source material checked for this page includes PaperMC profiling guide. If your server is Folia, Leaf, Purpur, Fabric, Forge, NeoForge, or another fork/loader, do not assume a Paper-only setting exists or behaves identically.
Verify the result
Repeat the same test with the same software build, player count and world activity. Compare the targeted symptom and any spark measurements, then check that intended game mechanics still work. If the change does not produce a reproducible improvement, revert to the recorded baseline.