Smooth Server

Server performance mods, packaged for Fabric.

Smooth Server brings together server performance mods for Minecraft Java 1.17.1 through 26.3, including the stable patch releases in between. It targets tick processing, memory use, redstone, terrain generation and networking. Install it on your Fabric server; players do not need this modpack on their clients.

Measured performance

We compared the unchanged published 26.3 Fabric-SmoothS v1 pack against Fabric 26.3 without mods across six synthetic workloads, with five paired repetitions each: 60 measured server runs. Fixture-validation pilots were excluded. Each trial started from a fresh copy of its workload's baseline-built world; configuration order alternated within pairs, with one server running at a time.

Tick computation and fresh terrain

Workload	Fabric without mods	Smooth Server	Less time with the pack	Paired outcome
Mixed control: 400 individually penned zombies with AI + 1,024 empty hoppers	2.010 ms/tick	0.810 ms/tick	59.7%	All 5 pairs improved
AI only: 400 individually penned zombies	1.610 ms/tick	0.760 ms/tick	52.8%	All 5 pairs improved
Idle hoppers: 4,096 empty, unpowered hoppers	0.390 ms/tick	0.020 ms/tick	94.9%	All 5 pairs improved
Active transfers: 256 independent four-hopper lanes between double chests	0.130 ms/tick	0.100 ms/tick	23.1%	All 5 pairs improved
Redstone: 16 clocked 13 x 13 dust grids	1.600 ms/tick	0.110 ms/tick	93.1%	All 5 pairs improved
Fresh terrain: eight batches of 64 new target chunks, 512 total	13.969 s	13.423 s	3.9%	Mixed / inconclusive

Values are medians of five runs per configuration; percentages compare those medians. Lower time is better. Tick rows measure computation during a 12,000-tick sprint after 4,000 warmup ticks and 60 seconds at normal cadence. The sprint removes the normal 20 TPS cap; its throughput does not establish production TPS or player capacity. Console sprint timings are rounded to 0.01 ms, which limits precision for very cheap workloads.

All five paired primary measurements improved in each tick workload. This describes consistency in these trials, not a statistical confidence claim. Terrain included a regressing pair, so its smaller median time is not a consistent or established terrain speedup. Terrain CPU time also increased by 4.6% in the median, with mixed paired outcomes.

Normal cadence and tradeoffs

At the normal 20 TPS target, median rolling average tick times were:

Workload	Fabric without mods	Smooth Server	Less time with the pack
Mixed control	4.2 ms/tick	2.2 ms/tick	47.6%
AI only	3.6 ms/tick	2.1 ms/tick	41.7%
Idle hoppers	1.2 ms/tick	0.2 ms/tick	83.3%
Active transfers	0.6 ms/tick	0.5 ms/tick	16.7%
Redstone dust	1.9 ms/tick	0.4 ms/tick	78.9%

These are console tick query rolling averages, not individual-tick percentiles. Active-transfer paired results were mixed at normal cadence; the other four workloads improved in every pair.

The pack did not improve every metric. Median resident Java process memory was 8.8-15.3% higher across the five tick workloads, and startup took 28.6-32.8% longer across all six workloads; every pair regressed on those measurements. Median normal-cadence CPU use increased from 0.013 to 0.041 core equivalents for idle hoppers (+207.4%) and from 0.026 to 0.048 for active transfers (+84.2%), with regressions in every pair. Those percentages start from small absolute CPU usage. Normal-cadence CPU results were mixed for mixed control, AI and redstone. Sprint CPU time decreased for mixed control, AI, idle hoppers and redstone in every pair; active-transfer sprint CPU results were mixed, with equal configuration medians.

Test conditions and scope

Tests used Windows 10 Pro, Temurin Java 25.0.4, Fabric Loader 0.19.5, a 2 GiB maximum heap and four processors visible to the JVM, with a 4 GiB process memory limit and 50% host CPU cap. There were no players; natural spawning, random ticks, day and weather cycles were disabled. Disk caches were warm and the JVM warmup was bounded; these were local tests on a shared host.

Fixture checks covered entity counts, active-hopper progress and item conservation, stocked sources throughout measurement, sustained redstone activity during normal cadence and sprint, and fresh terrain completion. Initial world hashes matched within each workload, and installed mod files and supplied configuration were checked against the published artifact. No measurement mods were added.

Terrain simulation was frozen, generation was warmed in a separate unmeasured region, and forced chunks were released between batches. Its timing covers terrain loading and preparation, including possible neighboring generation. Memory measurements describe the Java process working set, not just its heap.

Gains are attributed to the full pack, not isolated mods. Results apply to these synthetic workloads on Minecraft 26.3; they do not predict every world, machine, player load or other supported version. FPS and network throughput were not measured, and a lag-free server is not guaranteed. Benchmark suite reference: 20261011T195733Z-23636.

What the pack includes

Available mods vary with the Minecraft version. The 26.3 build includes:

• Lithium and ServerCore for server tick optimizations.
• FerriteCore and ModernFix-mVUS for memory and other performance improvements.
• Fast Noise and Structure Layout Optimizer for terrain and structure generation.
• Alternate Current for redstone dust optimizations, and Krypton for networking optimizations.
• Chunky for optional chunk pregeneration, and spark for diagnosing performance.
• TT20, No Chat Reports, Fabric API, Resourceful Config and the required ZConfig dependency.

Only compatible stable mod releases are selected. Missing mods are listed in each version's changelog; they are reconsidered when a compatible stable release becomes available. The 26.3 build is missing Async, C2ME, Immersive Optimization and ScalableLux.

Vanilla-focused, with technical differences

The pack adds no new content or progression systems. Some included mods affect technical behavior: Alternate Current changes redstone update order, and TT20 changes timing under low TPS, including fluids, random ticks and block breaking. Versions that include Immersive Optimization also reduce some entity ticking. No Chat Reports changes chat-reporting behavior. These choices should be considered when using sensitive farms or redstone builds; the pack is not a guarantee of identical vanilla behavior.

Choosing a version

Pick the file matching your exact Minecraft version. Fabric is the supported loader for the current automated releases.

The pack's channels indicate how much of its 18-project reference catalog is available:

• Release: zero to two reference projects missing.
• Beta: three to eight missing.
• Alpha: nine or more missing.

These labels describe pack completeness; installed mod releases are still stable. See the changelog for the actual omissions and changes.

Installation

Install the .mrpack with a server tool that supports Modrinth packs, using the Java version required by that Minecraft release. Keep a backup of your world and configuration when updating. Chunk pregeneration and profiling are optional tools; they do not run automatically as part of the pack's benchmark.