When The Elder Scrolls IV: Oblivion Remastered released last year, I was excited to revisit one of my all time favourite games, and the land of Cyrodiil. With a modern Unreal Engine 5 overhaul, it looked fantastic, but frankly, it ran like s***. Unfortunately, this is the case with many titles running on Unreal Engine 5, the celebratory mood was quickly dampened by severe CPU bottlenecks, erratic frame pacing, and relentless traversal stuttering that are synonymous with the engine. With official patches drying up fairly quickly, one frustrated PC gamer turned modder has decided to take matters into their own hands by turning Anthropic’s Claude AI loose on the game’s code… and it seems to have worked rather well.

Reddit user LTSharpe had been playing the original Oblivion since 2006 and expected a smooth experience in the remaster after upgrading from an NVIDIA GeForce RTX 2070 Super to an AMD Radeon RX 9070 XT. Paired with an AMD Ryzen 7 5800X processor and 32GB of DDR4 RAM, the system still struggled to maintain playable frame rates, regularly dropping to between 20 and 30 FPS in heavier areas like Cheydinhal regardless of how low the resolution or graphics settings were dialled back.

With spare tokens left over before a weekly subscription reset, they launched the game, tabbed out to Claude Opus 5.5, and asked it to figure out why the frame rate was tanking. Without using traditional reverse-engineering suites, the AI simply asked the user to link their GitHub account to the Epic Games to reference standard Unreal Engine source code alongside the running game. Claude quickly uncovered a massive flaw in how the remaster handled its rendering pipeline. The game was reconstructing the entire lighting of a scene on every single frame, even when nothing in the environment was changing. Worse still, all of that redundant work was being forced onto a single CPU thread, creating a massive processor bottleneck that choked modern graphics cards.

Encouraged by the initial discovery, LTSharpe upgraded to a higher-tier Claude plan and spent the next two and a half weeks running an automated optimisation workflow. Whenever they encountered a stutter-heavy area or performance drop in-game, they instructed Claude to build a custom benchmark around that specific scenario. While the user was away at work during the day, two Claude Opus 5.5 sub-agents worked autonomously on the home PC using a headless, silent benchmarking harness to test code adjustments, with the user checking progress remotely via a mobile app. In the evenings, LTSharpe tested the builds in-game and provided feedback for the next day’s pass. By the end of the project, the AI-assisted effort had produced a custom DLL modification featuring around 40 distinct code and engine optimisations.

• Eliminated redundant per-frame scene lighting reconstructions that were hammering a single CPU thread, distributing workloads more effectively across frames.
• Boosted frame rates inside demanding cities like Cheydinhal from around 30 FPS to a stable 60 FPS.
• Increased average open-world frame rates by 30% to 40% while significantly improving 1% lows and rendering traversal stutter almost unnoticeable.
• Implemented full support for the latest AMD FSR Frame Generation, including tailored optimisations to prevent stutter and ensure the game passes proper camera data.
• Resolved several legacy bugs originating from both the original 2006 game logic and the new Unreal Engine 5 wrapper code.
• Created an automated, headless benchmarking harness capable of testing and iterating on bottleneck scenarios without human intervention.

LTSharpe has released the resulting modification, titled OblivionRemasteredPerformanceFix, as an open-source beta on both GitHub and Nexus Mods. Because the user states they are not an IT developer by trade, fellow community members have already begun running adversarial code reviews to help iron out minor concurrency bugs and refine how frame generation metrics are measured. It is worth noting that because the fixes were developed and tested solely on an AMD Ryzen 7 5800X and Radeon RX 9070 XT configuration, mileage may vary on Intel processors or NVIDIA graphics cards until broader community testing takes place. Even so, the project works on both Windows and Linux via SteamOS using a simple DLL override launch command, offering a fascinating glimpse into how AI coding tools can help modders rescue poorly optimised PC ports that studios have left behind.

Check out the original post on reddit here, download the source on GitHub, or just grab the mod on Nexus Mods here.