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.