Diablo IV: Fixing Memory Leak via LocalPrefs.txt

The primary goal for stabilizing Diablo IV is managing the VRAM Buffer. The engine’s “Ultra” textures are uncompressed and can easily exceed 10GB–12GB of VRAM, leading to a memory leak as the system swaps data to the much slower Pagefile on your SSD. Modifying the LocalPrefs.txt allows us to implement a “Memory Stability” profile: forcing a stricter limit on Texture Quality and disabling the “Chromatic Aberration” and “Distortion” effects that contribute to GPU compute latency during dense Helltide encounters.

Hardware Compatibility & Expectations

• VRAM Threshold: If you have 8GB of VRAM or less, these tweaks are mandatory to prevent mid-dungeon crashes.
• Storage Speed: Even with these tweaks, Diablo IV requires an SSD. If you are on an older SATA SSD, setting the PeripheralLighting to 0 in the config can reduce secondary CPU hitches.
• DirectX 12 Agility: D4 uses modern DX12 features; ensure your Windows and GPU drivers are fully updated to support the latest “Shader Model 6.6” improvements.

Backup and Preparation

The LocalPrefs.txt is regenerated if deleted, but it is easier to keep a backup of your working settings.

1. Completely exit Diablo IV and the Battle.net Launcher.
2. Navigate to your Documents folder (path below).
3. Copy LocalPrefs.txt and save it to your desktop as a backup.
4. Open the original with Notepad++.

File Location

The configuration file is located in your local Diablo IV folder: C:\Users\%USERNAME%\Documents\Diablo IV\LocalPrefs.txt

Best LocalPrefs.txt Settings for Memory Stability

Search for these specific strings. Update the values to match this “Stutter-Fix” profile:

TextureQuality "1"
PhysicsQuality "1"
ShadowQuality "1"
ReflectionQuality "0"
ColorCorrection "0"
ChromaticAberration "0"
Distortion "0"
LowViolence "0"
SafeZone "0"
PeripheralLighting "0"

Pro Tip: Changing TextureQuality to “1” (Medium) in the config file is the most effective way to stop the memory leak. While “High” looks slightly better, the engine’s current allocation logic is flawed, and “Medium” provides the most stable frame-pacing for 8GB–10GB cards.

Key Parameters Explained

Parameter	Recommended Value	Impact
TextureQuality	“1”	Prevents VRAM overflow; stops the “stutter” during town portals.
PeripheralLighting	“0”	Disables RGB sync for keyboards/mice, which often causes micro-stutters.
Distortion / Chromatic	“0”	Removes post-processing “smearing” and reduces GPU compute load.
PhysicsQuality	“1”	(Medium) Reduces the CPU load when hundreds of monsters explode at once.
ReflectionQuality	“0”	Disables real-time floor reflections, a major VRAM and FPS saver in dungeons.

In-Game Settings vs. Config

To complement your memory-leak fix, match these in-game Graphics settings:

• Max Foreground FPS: Set this to your monitor’s refresh rate (e.g., 144). Leaving it “Uncapped” accelerates the memory leak as the engine pushes frames faster than it can clear the cache.
• DLSS / FSR / XeSS: Set to Quality. Using an upscaler reduces the internal render resolution, which saves a significant amount of “Temporary VRAM” during combat.
• NVIDIA Reflex: Set to Enabled. This keeps the input latency low even when the VRAM is nearing its limit.
• Clutter Quality: Set to Low. This reduces the amount of static “junk” (rocks, grass) the engine has to keep in memory.

Troubleshooting & Common Fixes

• Textures Look “Muddy”: If TextureQuality "1" is too blurry, try “2” (High) but ensure you set ShadowQuality to “0” to compensate for the VRAM usage.
• Game Crashes on Teleport: This is a classic memory leak symptom. Clear your DirectX Shader Cache via Windows “Disk Cleanup” and restart your PC.
• Settings Resetting: Diablo IV updates the .txt file frequently. Once satisfied, right-click LocalPrefs.txt, select Properties, and check Read-only.

Frequently Asked Questions (FAQ)

Conclusion and Expected Results

By manually refining your LocalPrefs.txt, you are forcing the Diablo IV engine to operate within a sustainable VRAM budget. You can expect the elimination of “teleport-stutters,” consistent frame rates during massive Helltide waves, and a much longer playtime before the engine requires a restart.