Tim Sweeny: "Developers are not optimizing properly their games in Unreal Engine 5"

At the recent Unreal Fest in Seoul, Epic Games CEO Tim Sweeney addressed a growing criticism: that Unreal Engine 5 (UE5) titles often struggle on less powerful hardware. His take? The engine isn’t inherently to blame — it’s how developers are using it.

Sweeney argued that many studios build for high-end PCs and consoles first, only attempting to optimize for lower-spec systems late in development. This “optimize at the end” approach, he says, is a major reason UE5 games can feel sluggish on mid-range GPUs or older consoles.

“The primary reason why Unreal Engine 5-based games don’t run smoothly on certain PCs or GPUs is the development process… Ideally, optimization should be implemented early in development, before full-scale content build begins.” — Tim Sweeney

UE5’s flagship features — Nanite (virtualized geometry) and Lumen (real-time global illumination) — are technical marvels, but they’re also resource-hungry. Without early optimization, these systems can overwhelm less powerful hardware.

Sweeney outlined two upcoming Epic initiatives:

Automated Optimization Tools — to streamline performance tuning across devices.
Expanded Developer Training — to instill early optimization habits and offer direct Epic engineering support when needed.

He also noted that Fortnite’s own optimization learnings are being folded back into UE5, aiming to make even low-spec PC performance viable.

📜 Historical Context

This isn’t the first time a game engine has faced a “blame the tech” narrative.

CryEngine in the late 2000s was notorious for “Can it run Crysis?” memes — often more about developer ambition than engine flaws.
Unity has faced similar debates, where asset-heavy projects without optimization tank performance despite the engine’s flexibility.

The UE5 conversation echoes these cycles: powerful tools can empower or overwhelm, depending on how they’re wielded.

Community & Industry Reactions

Reaction Type	Summary	Tone
Developer Agreement	Many indie and mid-tier devs admit late optimization is common, citing budget and milestone pressures.	🤝 Constructive
Player Skepticism	Some gamers feel Sweeney is deflecting blame from Epic, pointing to UE5’s heavy baseline requirements.	😒 Critical
Tech Realists	Hardware enthusiasts note that even well-optimized UE5 games will push older GPUs hard due to Nanite/Lumen.	🖥 Balanced
Optimism for Tools	Positive buzz around automated optimization features, especially for small teams without dedicated performance engineers.	🌟 Hopeful
Cynical Take	A few voices suggest Epic’s push for better optimization is also about protecting UE5’s reputation in the console space.	🕵️‍♂️ Suspicious

This moment is a microcosm of a larger truth in game development: technology is only as efficient as the workflows around it. UE5’s cinematic fidelity is a double-edged sword — it can democratize AAA visuals, but without disciplined optimization pipelines, it risks alienating players on anything but top-tier rigs.

For players, the takeaway is that performance isn’t just about your GPU’s horsepower; it’s about how early and effectively a studio plans for your hardware. For developers, Sweeney’s comments are a reminder that optimization isn’t a “polish pass” — it’s a design philosophy.

Do you think Epic’s new tools and training will meaningfully change UE5’s performance reputation, or is this a deeper cultural shift that will take years to stick?