The primary goal for Baldur’s Gate 3 Act 3 optimization is CPU Overhead Reduction. Unlike Acts 1 and 2, Act 3’s performance drops are rarely caused by lighting or textures; they are caused by “Dynamic Crowds” and script execution. This configuration focuses on lowering Instance Distance and Animation LOD, which directly impact how much the CPU has to calculate for NPCs you aren’t even looking at.
File Location
The graphicSettings.lsx file is located in your local AppData folder. Ensure the game and Larian Launcher are closed:
%LocalAppData%\Larian Studios\Baldur's Gate 3\graphicSettings.lsx
Technical Configuration (The 2026 “Act 3” Template)
Open the file with a text editor (like Notepad++). Search for the following <node id="ConfigEntry"> blocks and update the value attributes. These are calibrated to offload as much work from the CPU as possible:
<node id="ConfigEntry">
<attribute id="MapKey" type="FixedString" value="ModelDetail"/>
<attribute id="Type" type="int32" value="0"/> </node>
<node id="ConfigEntry">
<attribute id="MapKey" type="FixedString" value="AnimationLOD"/>
<attribute id="Type" type="int32" value="0"/> </node>
<node id="ConfigEntry">
<attribute id="MapKey" type="FixedString" value="InstanceDistance"/>
<attribute id="Type" type="int32" value="0"/> </node>
<node id="ConfigEntry">
<attribute id="MapKey" type="FixedString" value="DynamicCrowds"/>
<attribute id="Type" type="int32" value="0"/> </node>
<node id="ConfigEntry">
<attribute id="MapKey" type="FixedString" value="SlowHDDMode"/>
<attribute id="Type" type="int32" value="1"/> </node>Parameter Breakdown:
- AnimationLOD value=”0″: This forces NPCs in the distance to use simplified animations. In a crowded place like the Lower City, this can save significant CPU frame time.
- InstanceDistance value=”0″: Limits the distance at which small objects (clutter, debris) are rendered. This reduces the total “draw call” count, which is a major bottleneck in Act 3.
- DynamicCrowds value=”0″: While the city feels slightly less “busy,” this setting stops the game from calculating complex AI paths for the hundreds of generic “Citizen” NPCs, which is the #1 cause of Act 3 lag.
- SlowHDDMode value=”1″: Even if you have a Gen5 NVMe SSD, turning this on changes the asset streaming behavior to be less aggressive, which helps prevent those 1-2 second freezes when moving between city blocks.
Strategy for 2026 Act 3 Performance
To complement the XML changes and maintain a stable 60+ FPS:
- The “Registry” CPU Priority Fix: Since BG3 is often ignored by Windows’ “Game Mode” logic, you can force it to High Priority.
- Tip: Create a
.regfile with the following to force thebg3_dx11.exeto a higher CPU priority class.
- Tip: Create a
- API Choice (DX11 vs Vulkan): In 2026, DirectX 11 remains the most stable for NVIDIA users in Act 3. Vulkan can offer higher peak FPS but is prone to memory leaks that become apparent after 2+ hours of play in the city.
- Frame Generation (DLSS 3 / FSR 3): If your GPU supports it, Frame Generation is mandatory for Act 3. Because Act 3 is CPU-bound, typical upscaling (DLSS Quality/Performance) won’t help much. Frame Gen bypasses the CPU bottleneck by generating frames entirely on the GPU.
- The “Clear Cache” Routine: Act 3 stores a massive amount of “LevelCache” data. Every 10-15 hours of play, navigate to
%LocalAppData%\Larian Studios\Baldur's Gate 3\LevelCacheand delete the contents. This often fixes the “decaying performance” issue.
Key Performance Parameters
| Parameter | Recommended Value | Impact |
| Model Quality | Low | Reduces CPU-to-GPU draw call overhead. |
| Dynamic Crowds | Disabled (0) | The single biggest fix for Act 3 stability. |
| Clouds/Fog | Medium | Saves GPU headroom for higher resolutions. |
| Slow HDD Mode | Enabled | Reduces stuttering during city traversal. |
Frequently Asked Questions (FAQ)
Why did my FPS drop 50% as soon as I entered the Lower City?
This is normal. The game transitions from rendering small, controlled groups of NPCs in Acts 1 & 2 to a massive, persistent urban environment. Your CPU is likely struggling with the sheer volume of “scripts” running for the citizens.
Does “Dynamic Crowds” remove the people?
No, it simply simplifies their AI and reduces the density of non-interactive NPCs. You will still see people, but they won’t be “thinking” as hard, which saves your CPU.
Is there a “Memory Leak” in Act 3?
Yes. Even in 2026, many players report that performance degrades after 2-3 hours of playing in the city. Restarting the game is the only consistent fix for this.
Should I use “Skip Launcher”?
Yes. Use the Steam launch option --skip-launcher. The Larian Launcher can occasionally hang in the background and consume up to 5-10% of your CPU, which you need for the city.
Conclusion and Expected Results
By manually forcing Low Animation LOD and disabling Dynamic Crowds in your graphicSettings.lsx, you are addressing the specific “Citizen AI” bottleneck that plagues Act 3. You can expect a much more stable frame time, the removal of major “traversal stutters” while walking through the city gates, and a more responsive UI during combat in crowded areas.