Valheim Performance Overhaul

A comprehensive performance optimization mod focused on reducing CPU and GPU load — especially on large bases, busy servers, and zones with many light sources.

Installation

Install via r2modman or Thunderstore Mod Manager (recommended) — everything is placed automatically.

Manual install:

1. Install BepInExPack Valheim first.
2. Copy ValheimPerformanceOverhaul.dll into BepInEx/plugins/.
3. Launch the game — a config file is generated automatically at BepInEx/config/com.Skarif.ValheimPerformanceOverhaul.cfg.

What it does

🔦 Light Culling (biggest FPS impact)

• Limits active light sources to a configurable maximum (default: 15).
• Disables shadow casting beyond a set distance.
• Light LOD system: transitions lights through Full → No Shadows → Emissive → Billboard → Disabled as distance increases.

🕯️ Light Flicker Optimization (new in 2.7.0)

• Fixes fire and torch light intensity at its base value, eliminating per-frame Shadow Map recalculation.
• In vanilla, every flickering campfire forces the GPU to fully rebuild shadow maps each frame for all objects in its radius. Freezing the intensity makes the light static — shadows are computed once and reused until something moves.
• Especially impactful on large bases with many fires, hearths, and torches.

💤 Distance Culler

• Puts distant creatures and building pieces to "sleep" — pauses their Update logic.
• Physics culling for Rigidbodies beyond a set range.
• Configurable exclusions (e.g. portals, tombstones are never culled).

🏗️ Piece Optimization

• WearNTear.GetSupport() results are cached with a configurable TTL.
• Distant pieces skip their Update cycle entirely.
• Asynchronous WearNTear initialization — spreads load over multiple frames on scene load.

🤖 AI Throttling

• Monsters beyond 60 m update AI only every 5 seconds instead of every frame.
• LOS (line-of-sight) checks are cached per-target with a 0.5 s timeout.
• Idle tamed animals inside player bases enter a low-power mode.

🌫️ Smoke Physics Optimization (new in 2.7.0)

• Replaces complex vanilla smoke aerodynamics with a simple, lightweight approximation.
• Vanilla smoke particles push each other, compute volumes, and simulate accumulation under rooftops. On large bases with many campfires this creates hundreds of per-frame collision checks between particles and building geometry.
• The simplified version uses quadratic interpolation for particle mass and a single upward force — smoke still rises and fades, but at a fraction of the CPU cost.

🎨 Graphics Settings

• Configurable shadow distance, resolution, and cascade count.
• Bloom and screen-space reflections toggle.
• Terrain quality multiplier.

⚙️ Engine Quality Settings (new in 2.7.0)

• Forces low-level Unity QualitySettings tweaks at startup:
  • Soft Particles disabled — eliminates per-pixel Depth Buffer reads for particle edges.
  • Soft Vegetation disabled — removes the extra GPU pass for grass and bush border blending.
  • Particle Raycast Budget reduced (default: 1024, vanilla: 4096) — limits per-frame ray-casts fired by particle systems for collision checks.
• Minor visual change on particle edges; significant GPU and CPU gain on particle-heavy scenes.

🌿 Vegetation

• Grass render distance and density control.
• Detail object distance and density.

🎵 Audio Pooling

• Reuses AudioSource components instead of creating new ones per sound effect.

♻️ Object Pooling

• Reuses ItemDrop GameObjects to reduce instantiation overhead when loot spawns.

🧠 GC Control

• Prevents Unity's garbage collection from firing during combat or movement.

⚡ JIT Warm-up

• Pre-compiles critical game methods on spawn to eliminate the first-use stutter.

🛡️ Frame Budget Guard (new in 2.7.0)

• Monitors frame times in a rolling 120-frame window (~2 seconds) and tracks the 1% Low — the average duration of the worst frames.
• When heavy spikes are detected (configurable threshold, default: 28 ms), dynamically lowers Time.maximumDeltaTime to prevent Unity's physics engine from entering the Death Spiral: lag → engine tries to catch up physics → even more lag → multi-second freeze.
• Converts hard freezes (e.g. large structure collapse) into brief slow-motion, preserving input responsiveness. Returns to normal automatically once the game stabilises.

🗺️ Minimap Optimization

• Configurable texture resolution and update frequency.

⏩ Skip Intro (new in 2.7.0)

• Skips the Iron Gate and Coffee Stain logo screens on every game launch.
• Saves 5–10 seconds per startup. No FPS impact — pure convenience.

Configuration

All settings are available in BepInEx/config/com.Skarif.ValheimPerformanceOverhaul.cfg.

If you have BepInEx Configuration Manager installed, press F1 in-game to adjust all settings with a GUI in real time.

Key settings

Performance expectations

Results depend heavily on scene complexity. Typical gains:

Compatibility

• ✅ Works standalone — no other mods required.
• ✅ Compatible with most content mods (Epic Loot, Jotunn-based mods, etc.).
• ⚠️ If Object Pooling conflicts with a loot mod, disable it in config (4. Object Pooling → Enabled = false).
• ⚠️ Light Flicker Optimization removes the visual flicker from fires and torches. If you prefer the vanilla animated flame appearance, disable it in config (17. Light Flicker Optimization → Enabled = false).
• ⚠️ Smoke Physics Optimization changes smoke behaviour — particles will no longer accumulate under rooftops. Disable in config if this is important to you (18. Smoke Physics Optimization → Enabled = false).
• ⚠️ The mod is in BETA. Test runs have been conducted in various situations, but it is advisable to keep world backups.
• ❌ Does not support crossplay (Steam + Game Pass mixed sessions). Pure Steam servers are fine.

Changelog

v2.7.1

Added

• mini-update (smokePatch).

v2.7.0

Added

• Light Flicker Optimization — Harmony Prefix on LightFlicker.CustomUpdate that fixes light intensity at its base value, eliminating per-frame Shadow Map recalculation for all fires and torches. Significant GPU gain on bases with many light sources.

• Smoke Physics Optimization — Harmony Prefix on Smoke.CustomUpdate that replaces the vanilla complex aerodynamics (inter-particle collisions, volume simulation, roof accumulation) with a lightweight quadratic interpolation + single upward force. Dramatic CPU savings on large bases with many campfires. Lift force is configurable.

• Engine Quality Settings — Forces low-level Unity QualitySettings at startup: softParticles = false, softVegetation = false, configurable particleRaycastBudget (default: 1024 vs vanilla 4096). Minor visual change on particle edges; measurable GPU and CPU gain in particle-heavy scenes.

• Skip Intro — Skips Iron Gate and Coffee Stain logo screens on every game launch by patching SceneLoader.Start. Saves 5–10 seconds per startup.

• Frame Budget Guard — Dynamic stutter protection system. Monitors a rolling 120-frame window, computes the 1% Low frametime, and lowers Time.maximumDeltaTime when heavy spikes are detected. Prevents Unity's physics Death Spiral (lag → engine over-simulates physics to catch up → more lag → freeze). Converts hard freezes into brief slow-motion. All thresholds are configurable. Automatically recovers when the game stabilises.

Changed

• Version bumped to 2.7.0.
• README updated with new module descriptions, expanded compatibility notes, and updated performance expectations table.
• Config sections renumbered: new modules occupy sections 17–21.

Notes

• All new modules are enabled by default and can be individually toggled in config.
• Light Flicker and Smoke optimizations are Prefix patches with return false — they fully replace vanilla logic. If you experience unexpected visual issues with fires or smoke, disable the relevant module.
• Private game fields are accessed via AccessTools.Field (cached) and Traverse — no direct decompiled references, compatible with future game updates.

v2.6.4

Added

• Nothing (maintenance release).

v2.6.3

Added

• Welcome screen on main menu launch.
  • Displays a feedback message on first launch.
  • Clickable link to Steam profile for bug reports and suggestions.
  • "Don't show anymore" checkbox to permanently hide the screen.

v2.6.0

Changed / Fixed

• Removed NetworkManager (ZSteamSocket-only implementation, broke crossplay).
• Removed ZDOOptimizer (potential desync risk on servers).
• Fixed LightLODManager: removed duplicate ScanForLights() call on Start.
• Fixed AdvancedLightManager: removed periodic FindObjectsByType scan every 5 s (caused micro-freezes).
• DistanceCuller refactored: all cullers now managed by one central Update loop instead of one Update() per object.
• PiecePatches: replaced ConcurrentDictionary with Dictionary (main thread only, 3–5× faster lookup).
• AsyncWearInit: added early exit when queue is empty.

v2.5.1

• Initial public release.

Changelog

v3.0.0

Added

• Decor Batching (New Module): Automatically combines meshes of decorative pieces (Misc category, no WearNTear) in a chunk grid to drastically reduce draw calls on large bases. Configurable rebuild cooldown and minimum pieces per chunk.
• In-Game Settings Menu: Added a built-in VPO configuration menu accessible directly from the Main Menu. No longer requires external BepInEx Configuration Manager to tweak settings.
• Network Optimizations (Crossplay Safe!): Brought back and completely rewritten to safely support Game Pass / Crossplay:
  • Steam Socket Uncap: Increases P2P data limits (solves lag on huge bases). Safely disables itself if not running on Steam.
  • Adaptive Throttling: Intelligently drops ZDO sends to clients with high ping (>400ms) to prevent choking their connection.
  • Smart ZDO Sorting: Prioritizes players, portals, and ships over AI during network sync to prevent desyncs.
  • Smart Zone Ownership: Automatically transfers AI control to the player with the lowest ping in the zone.
• Piece Sleep Manager: Puts static building pieces (WearNTear) to sleep after 2 frames of inactivity, saving CPU cycles on massive structures.

Changed / Optimized

• Zero GC Allocations on Hot Paths: Replaced expensive Reflection (GetValue/SetValue) with compiled Expression delegates. Completely eliminates boxing (float -> object) and garbage generation per frame in:
  • LightFlickerPatch (v2.8.0)
  • VegetationPatches (v2.8.1)
  • SmokePatch (v2.9.0)
  • ObjectPoolManager
• O(1) Collection Upgrades: Upgraded DistanceCullerManager, AIOptimizerManager, and AudioPoolManager to use HashSet alongside List. This changes duplicate checking from O(n) to O(1), fixing massive O(n²) lag spikes when loading chunks with thousands of objects.
• Smoke Physics Overhaul: AddForce is now throttled to run once every 3 physics frames. Rigidbody mass updates are throttled to 0.1s. isKinematic and Rigidbody references are now heavily cached.
• Tamed Idle Optimizer: Optimized base detection using LayerMask directly in Physics.OverlapSphere, avoiding expensive GetComponentInParent traversals on hundreds of colliders.
• Object Pooling: Optimized IsInWhitelist to use GetStableHashCode, completely avoiding string allocations (Replace, Trim) on the hot path. Removed unnecessary thread lock statements since pooling is strictly single-threaded, reducing overhead.
• AdvancedLightManager & FrameBudgetGuard: Cached Comparer delegates to avoid lambda allocations multiple times per second.

Fixed

• [CRITICAL] Smoke Memory Leak: Fixed a critical vanilla issue (and previous patch oversight) where smoke objects were never destroyed after fading out. Hundreds of invisible smoke objects would accumulate and tick in FixedUpdate, killing FPS over time.
• [CRITICAL] Light Culling Conflict: Fixed a severe conflict where AdvancedLightManager and LightLODManager both patched ZNetScene.CreateObject and fought over light states. Registration is now unified.
• Zombie Lights Bug: Fixed a bug in AdvancedLightManager where destroyed lights weren't removed from the _culledLights list, causing zombie references that permanently broke the active lights limit.
• Animator Conflict: Fixed a bug where AIOptimizer and CharacterAnimatorOptimizer were fighting over Animator.cullingMode in the same frame.
• Support Cache: Added ZNetScene_OnDestroy_Postfix to clear the invalidation queue on scene unload, preventing null reference errors when changing worlds.

v2.7.1

Added

• mini-update (smokePatch).

v2.7.0

Added

• Light Flicker Optimization — Harmony Prefix on LightFlicker.CustomUpdate that fixes light intensity at its base value, eliminating per-frame Shadow Map recalculation for all fires and torches.
• Smoke Physics Optimization — Harmony Prefix on Smoke.CustomUpdate that replaces the vanilla complex aerodynamics with a lightweight quadratic interpolation + single upward force.
• Engine Quality Settings — Forces low-level Unity QualitySettings at startup: softParticles = false, softVegetation = false, configurable particleRaycastBudget.
• Skip Intro — Skips Iron Gate and Coffee Stain logo screens on every game launch.
• Frame Budget Guard — Dynamic stutter protection system. Monitors a rolling 120-frame window and lowers Time.maximumDeltaTime when heavy spikes are detected.

Changed

• Config sections renumbered: new modules occupy sections 17–21.

v2.6.4

Added

• Nothing (maintenance release).

v2.6.3

Added

• Welcome screen on main menu launch with clickable Discord link.

v2.6.0

Changed / Fixed

• Removed NetworkManager and ZDOOptimizer temporarily (crossplay issues).
• Fixed LightLODManager duplicate scans.
• DistanceCuller refactored to central Update loop.
• AsyncWearInit early exit when queue is empty.

v2.5.1

• Initial public release.