Epic Games Engineers Reveal the 7 Causes of Unreal Engine Issues

Unraveling The Top 7 PC Performance Challenges in Unreal Engine Games at Unreal Fest 2025

During Unreal Fest 2025 in Orlando, Epic Games Senior Engineer Ari Arnbjornsson delivered a session titled “The Great Hitch Hunt.” The presentation addressed common stuttering and freezing issues in PC games developed with Unreal Engine, pinpointing their primary causes and offering practical solutions. Arnbjornsson outlined seven key performance challenges in Unreal Engine-powered games. A primary cause is level streaming, which dynamically loads and unloads parts of the game world. Overusing individual objects (e.g., tables or books) instead of optimized structures like Static Meshes Instanced (SMIs) can strain the graphics engine’s memory and the garbage collection system. Epic Games is experimenting with solutions, such as Cell Transformers in Unreal Engine 5.5, which aims to automatically correct this issue during gameplay. Physics also poses a significant challenge. Arnbjornsson clarified that the Nanite system does not automatically handle collision simplification, contrary to some developers’ beliefs. He advised using simple shapes (e.g., spheres and boxes) for collisions whenever possible and disabling collisions for distant objects that do not require interaction. While Epic is testing asynchronous physics reset, it is not yet recommended for commercial games.

Optimizing Unreal Engine Performance: Addressing 5 Challenges in PC Gaming

Another concern is the creation of characters and objects. Generating complex characters with multiple parts, especially in large quantities, can cause performance drops. Potential solutions include limiting the number of creations per frame or recycling existing actors through actor pooling. Although not a built-in engine feature, this approach may become more viable in the future. Pipeline State Object (PSO) compilations can create bottlenecks, particularly on PCs due to hardware diversity, in contrast to the more straightforward process on consoles. Epic addresses this by precaching PSOs in Unreal Engine 5.3 and providing tools like the PSO Cache Buster to help studios detect and optimize these issues proactively. Garbage collection, if not managed efficiently, can cause delays when numerous unused objects accumulate. Epic is developing incremental accessibility analysis and multithreaded garbage collection to mitigate these impacts. The fifth issue involves synchronous loading of resources, which halts the game’s main process until a file fully loads, leading to execution delays. Arnbjornsson recommended exclusively using asynchronous loading and highlighted tools designed to identify and eliminate related bottlenecks.

Enhancing Unreal Performance: Tackling Blueprint Complexity with Unreal Insights Tool

Finally, excessive logic within Blueprints, such as complex timers and animations, can cause system instability. Epic plans to enhance the Unreal Insights tool to assist developers in identifying and resolving these problems. Arnbjornsson’s presentation served as a crucial technical reminder for production teams: despite advancements in hardware and Unreal Engine updates, active optimization and clever workarounds for engine limitations remain essential. Epic anticipates that adherence to these guidelines will lead to significant performance improvements, especially for PC games built with the engine.

In Case You Missed It

For fans of DC Comics and AAA gaming experiences, we have some exciting news! Sophie Laurent’s recent post on July 29th delves into Warner Bros. Games Montreal’s ambitious new project—a living service game set within the iconic DC universe, crafted with Unreal Engine 5. With a focus on delivering continuous content and player engagement, this title promises to be a standout addition to the DC gaming library. To learn more about the development plans and the studio’s vision for this innovative approach, check out WB Games Montreal Developing DC Comics Service Game. For those keeping up with the latest in gaming news, especially concerning Warner Bros. Games’ ambitious projects, be sure to check out our recent post titled “Even After Failures, Warner Bros. Games Continues Production of Another Service Game” by Marcus Thompson (July 29, 2025). The article delves into the company’s plans for a new DC Comics-based live service game, set to be developed using Unreal Engine 5 and aiming for top-tier production standards. With WB Games Montreal leading the charge, this project is shaping up to be another significant entry in Warner Bros.’ expanding gaming portfolio. Dive deeper into the details and join us in speculating about its potential success at Even After Failures, Warner Bros. Games Continues Production of Another Service Game. For those interested in the future of Warner Bros. Games and their strategic moves into live service games, be sure to check out “Warner Bros. Games Developing New ‘Live Service’ Game” by Ahmed Hassan (published on July 29, 2025). The post delves into the studio’s recent job listings hinting at a significant shift towards more profitable franchises like DC, Harry Potter, Mortal Kombat, and Game of Thrones. With insights on their focus to limit content production to only four high-yielding properties, this piece offers valuable context following the mixed reception of Gotham Knights. Dive deeper into these exciting developments Warner Bros. Games Developing New ‘Live Service’ Game.

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