What Clumps changes
Clumps by Jaredlll08 reduces the number of experience-orb entities around busy XP sources. Nearby orbs can combine into fewer entities, and touching an orb processes its stored experience immediately rather than feeding it to the player through the usual pickup delay. It is especially useful around mob grinders and concentrated XP drops, not a general replacement for diagnosing server lag.
This guide covers Clumps 19.0.0.1 for Minecraft Java 1.21.1 on NeoForge, released on 13 August 2024. Use that loader-specific file rather than treating every download named Clumps as interchangeable. Other Minecraft versions have separate builds and may behave differently. Official release
Install it where the world runs
For multiplayer, install Clumps in the NeoForge server's mods folder and restart the server. Players do not need their own Clumps installation for this release: the author's instructions say that Minecraft 1.17 and newer require it only server-side. A client-only installation cannot add its merging behavior to a remote server that lacks the mod. Other mods in the pack may still impose their own client requirements.
For single-player, put the NeoForge build in that instance's mods folder; the integrated server runs inside your game. Use Java 21 and a Minecraft 1.21.1 NeoForge instance. The release was built against NeoForge 21.1.8, which is a build reference, not a claim that every other build is incompatible. Its metadata requires Minecraft and NeoForge, with no separate library mod listed. Fabric API is not a dependency of this NeoForge file. Installation notes · Build versions
How merging and pickup work
Clumps broadens the orb-merging checks and retains a record of XP values and their counts. It does not simply count visible orbs: a merged entity can represent several original values. As an illustration, a 3-point orb and a 7-point orb represent 10 XP after merging, not two XP and not 10 levels.
The creation-time merge path searches a one-block-wide box centered on the XP spawn position for an existing orb. That is a local merge check, not a one-block player magnet or a farm-wide collection radius. Separated drops can remain separate until the normal orb behavior brings them close enough to merge or be collected.
On player contact, the mod clears the XP pickup delay, processes the stored entries, awards any remaining experience, and removes the collected entity. It does not invent extra XP or collect every orb across a room. Fewer orb entities can reduce work in XP-heavy areas, but there is no universal FPS or tick-rate improvement to promise. Merging and pickup implementation
Understand where the XP went
Clumps processes equipment repair before adding leftover XP to the player's experience bar. Its pickup loop handles the stored original orb values and counts, rather than assuming the entire clump is one repair payment. On NeoForge, it also uses the item's XP repair ratio and exposes events that other mods can affect.
If a pickup barely moves the XP bar, inspect damaged Mending equipment before concluding that XP disappeared. For a simple comparison, collect a small batch without eligible damaged Mending gear, then repeat while holding or wearing one damaged Mending item. Watch both durability and the XP bar. Other equipment, enchantment changes, or XP-handling mods can complicate that comparison. Repair integration
Check the right problem
If nothing changes, verify that the server actually loaded Clumps and that the JAR matches Minecraft 1.21.1 and NeoForge. Do not mix Forge, Fabric, and NeoForge files. There is no crafting recipe or activation key to unlock before merging begins.
If pickup or repair behaves strangely in a large pack, reproduce it in a backed-up test instance with only NeoForge and Clumps, then compare with the full pack. The NeoForge integration participates in XP pickup events, so another mod can influence the result. Report the exact versions, reproduction steps, and relevant logs rather than assuming every stalled orb is a Clumps bug. NeoForge pickup integration
Clumps FAQ
Does Clumps increase XP rewards?
No. It combines stored XP values; Mending and other mods can affect how much reaches the experience bar. XP points and XP levels are different quantities.
Must everyone install Clumps on a multiplayer server?
Not for Minecraft 1.21.1. Install it on the server; Clumps itself does not require matching client installations.
Why is the farm still lagging?
Clumps targets experience orbs. Mob AI, dropped items, machines, chunk activity, and rendering can still be bottlenecks; measure the actual cause rather than expecting an XP optimization to fix everything.
Does Clumps break Mending?
The inspected release explicitly handles item repair before awarding remaining XP. Test eligible damaged equipment and isolate other XP or enchantment mods if results differ from expectations.