Performance Struggles of Some Unreal Engine Games And How to Fix Them?
By
ChicMic Studios
March 18, 2025
Unreal Engine is recognizably among the most powerful game engines available in the market and used for Unreal game development across various platforms. It provides advanced rendering capabilities, realistic physics, and flexibility that make it a top choice for developers worldwide. Yet, despite its capabilities, many Unreal Engine games suffer from performance issues, ranging from low frame rates to excessive memory consumption. It doesn’t matter whether working as an Unreal game development company or an independent developer; it’s vital to understand these performance challenges and how to optimize them is crucial for delivering a smooth gaming experience. Join ChicMic Studios and explore why some Unreal Engine games struggle with performance and discover actionable solutions to fix these issues.
Common Performance Issues in Unreal Engine Games
1. Poorly Optimized Assets
Among the most primary reasons for performance bottlenecks in 2D/3D game development services is the use of unoptimized assets. High-polygon models, large texture sizes, and excessive draw calls can quickly overwhelm the engine, leading to lag and reduced performance.
Game developers often prioritize visual quality over optimization, which can lead to excessive texture resolutions or overly detailed models that strain the GPU. Additionally, inefficient UV mapping and excessive material usage can increase rendering times, making the game sluggish, especially on lower-end hardware.
2. Inefficient Level Streaming
Unreal Engine allows for level streaming, enabling developers to load and unload sections of a game world dynamically. If implemented incorrectly, levels may load inefficiently, causing frame rate drops and increased memory usage.
Large, open-world environments in mobile game development require seamless level streaming to prevent lag and stuttering. Failing to properly implement World Partitioning or streaming volumes can cause the engine to struggle, leading to sudden loading pauses and performance degradation.
3. Excessive Overdraw in Rendering
Overdraw occurs when multiple transparent layers are rendered on top of each other. In games with complex particle effects, UI elements, or overlapping textures, this can significantly impact GPU performance, leading to frame rate drops.
Developers often overlook overdraw issues when designing VFX-heavy scenes, resulting in unnecessarily high GPU loads. Unreal Engine’s Shader Complexity View Mode helps identify excessive overdraw, allowing developers to optimize materials and reduce unnecessary blending operations.
4. CPU Bottlenecks from Blueprints
Blueprints are an excellent tool for rapid prototyping and development in Unreal game development, but excessive reliance on them can lead to CPU bottlenecks. Unlike C++, which compiles into efficient machine code, Blueprints introduce additional processing overhead that can slow down the game.
Blueprint-based logic is easy to create but may not be as efficient as hand-optimized C++ code. Heavy calculations, frequent event ticks, and inefficient loops in Blueprints can significantly impact CPU performance. Thus, it can make real-time responsiveness challenging in high-action gameplay.
5. Heavy Physics and Collision Calculations
Unreal Engine’s physics engine is highly sophisticated, but excessive physics calculations or poorly optimized collision settings can cause unnecessary CPU load. Objects with complex collision meshes, high-frequency physics updates, or unnecessary simulations can contribute to performance issues.
Physics-heavy games, especially those featuring destructible environments or large-scale simulations, must carefully manage collision complexity and rigid body simulations. Simplified collision boxes and reduced physics update frequency can help improve performance.
6. Poorly Optimized AI and Pathfinding
AI-driven characters require pathfinding, decision-making, and behavior processing, all of which consume CPU resources. Without proper optimization, AI logic can create performance spikes, especially in large-scale environments.
For Unreal game development services, designing efficient AI involves limiting unnecessary path recalculations, optimizing behavior trees, and using event-driven AI updates instead of continuous loops that consume excessive CPU power.
7. Excessive Use of Dynamic Lighting and Shadows
While dynamic lighting adds realism to Unreal game development, overuse of dynamic shadows, real-time reflections, and global illumination can significantly impact performance. These effects are GPU-intensive and require optimization to balance quality and performance.
Using pre-baked lighting solutions or static shadows for non-interactive elements can help reduce unnecessary real-time calculations.
8. Inefficient Garbage Collection and Memory Management
Unreal Engine has an automatic garbage collection system to manage memory, but excessive object creation and deletion can cause performance hiccups. Poor memory management can lead to frequent garbage collection cycles, resulting in frame rate stuttering.
Games that create and destroy objects dynamically, such as spawning enemies or UI elements, must ensure object pooling is used effectively to minimize memory overhead and garbage collection interruptions.
How to Fix Unreal Engine Performance Issues
1. Optimize Game Assets
– Use LOD (Level of Detail) models to reduce polygon counts in distant objects.
– Compress textures and use efficient formats like DXT or ASTC for mobile game development.
– Reduce unnecessary materials and shaders to minimize GPU load.
– Implement texture streaming and mipmapping techniques to balance quality and performance.
2. Improve Level Streaming Efficiency
– Divide large maps into smaller, manageable sub-levels.
– Load assets asynchronously to prevent sudden frame drops.
– Use World Partitioning and streaming volumes to optimize asset loading dynamically.
3. Reduce Overdraw and Optimize Rendering
– Use Masked Materials instead of transparent materials whenever possible.
– Reduce overlapping particle effects and limit the use of high-density fog.
– Enable Occlusion Culling to prevent the engine from rendering objects not visible to the player.
– Utilize Instance Static Meshes to reduce draw calls and GPU load.
4. Convert Blueprint Code to C++ Where Necessary
– Use Blueprints for high-level logic and C++ for performance-intensive tasks.
– Profile and identify performance-heavy Blueprints using the Unreal Engine Profiler.
– Convert performance-critical functions and loops to C++ to improve execution speed.
5. Optimize Physics and Collision Settings
– Use simple collision meshes instead of complex per-triangle collisions.
– Reduce the number of objects with real-time physics calculations.
– Optimize physics tick rates to balance accuracy and performance.
6. Improve AI Efficiency
– Limit AI updates per frame to prevent CPU bottlenecks.
– Use Navigation Mesh (NavMesh) optimization to streamline pathfinding calculations.
– Implement behavior trees efficiently to reduce redundant computations.
7. Balance Dynamic Lighting and Shadows
– Use Static and Stationary lights where possible instead of fully dynamic lights.
– Reduce the number of dynamic shadows and shadow-casting objects.
– Bake lighting for static environments to reduce real-time calculations.
8. Manage Memory and Garbage Collection
– Avoid frequent object creation/destruction; reuse objects when possible.
– Use memory pools for frequently used objects to reduce garbage collection overhead.
– Profile and monitor memory usage to identify leaks or excessive allocations.
Conclusion
Performance issues in Unreal game development are common, but they can be mitigated with proper optimization strategies. Whether developing for high-end consoles or mobile game development, balancing performance and visual quality is essential for a smooth user experience. When developers understand the key areas that affect performance—such as asset optimization, efficient rendering, and memory management—it allows them to ensure their games run efficiently without compromising on quality. An Unreal game development company that prioritizes performance optimization can create immersive, seamless experiences across all platforms, setting their projects apart in a competitive industry.
