Iodium

Smarter chunk invalidation for VulkanMod — because not every block change deserves a full cache bust.

🔬 What is Iodium?

Iodium is a client-side performance mod that optimizes how VulkanMod handles chunk section invalidation during block updates.

Every time a block changes, VulkanMod calls setSectionDirty on the affected chunk sections — which internally removes them from the render region cache and queues a rebuild. The problem? This happens every single time, even if that section was already queued for a rebuild three calls ago.

During an explosion, a piston sequence, or rapid mining, this can mean hundreds of redundant cache invalidations per frame — all doing the same work, all for nothing.

Iodium fixes this.

⚙️ How it Works

Iodium tracks which chunk sections have been marked dirty over a rolling 5-frame window. When a section is already in the dirty set, subsequent invalidation calls for that section are skipped entirely — no redundant cache busts, no wasted work.

Without Iodium:
  Block A changes → setSectionDirty → cache invalidated ✓
  Block B changes → setSectionDirty → cache invalidated (again) ✗ wasted
  Block C changes → setSectionDirty → cache invalidated (again) ✗ wasted
  Block D changes → setSectionDirty → cache invalidated (again) ✗ wasted

With Iodium:
  Block A changes → setSectionDirty → cache invalidated ✓
  Block B changes → already dirty   → skipped           ✓ saved
  Block C changes → already dirty   → skipped           ✓ saved
  Block D changes → already dirty   → skipped           ✓ saved

After 5 frames the tracking resets, ensuring sections are always re-evaluated and nothing gets stuck.

📈 Where You'll Feel It

Scenario	Impact
💥 TNT / Explosions	Very High — dozens of sections dirty at once
⛏️ Rapid Mining or Building	High — continuous per-block invalidations
🌊 Fluid Spread (water, lava)	High — wave-like section updates
🔴 Redstone Chains	Medium — cascading block updates
🌄 Normal Exploration	Low — but still reduces background noise

Compatibility

Mod	Status
✅ VulkanMod	Required
✅ Lithium	Compatible
✅ Nvidium	Compatible
❌ Sodium	Incompatible — use Plutonium244 instead of Iodium
❌ Iris Shaders	Incompatible

Using Sodium instead of VulkanMod? Check out Plutonium244 — the sibling mod built for the Sodium pipeline with subchunk-level dirty tracking.

📦 Installation

Install Fabric Loader ≥ 0.19.3
Install Fabric API
Install VulkanMod
Drop Iodium into your mods folder
Launch and enjoy

📋 Requirements


Minecraft	26.1.2
Fabric Loader	≥ 0.19.3
VulkanMod	Any version
Java	25+
Side	Client only

👨‍🔬 About

Made by BlackGiack — also the author of Plutonium244, the Sodium equivalent of this mod.

Both mods share the same philosophy: don't do work that's already been done.

The name Iodium comes from Iodine (I, element 53) — because sometimes a small element makes all the difference.