NVIDIA has confirmed that one of the most recent Windows 11 security updates (KB5066835) for Windows 11 version 25H2 and 24H2 has caused performance to tank in some games when using a GeForce RTX graphics card. As one of those mandatory Windows updates, it's the latest in a long line of Microsoft releases that have caused unwanted issues.
The good news is that NVIDIA has released a Hotfix Driver that resolves the issue, so if you're one of those people who keep their Windows updated and have a GeForce RTX graphics card, be sure to download and install GeForce Hotfix Display Driver Version 581.94.
NVIDIA doesn't specify which games are affected, other than the information that this new Hotfix or Beta driver fixes the "Lower performance may be observed in some games after updating to Windows 11 October 2025 KB5066835" issue. However, per this X post by Sebastian Castellanos, it looks like Assassin's Creed Shadows is one of the games that saw performance take a hit.
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As seen in the chart, the GeForce Hotfix Display Driver Version 581.94 delivers a massive performance boost (or fix, as it were), with the frame rate jumping from 149.7 FPS to 220.3 FPS. That's close to a 50% difference, so this is a pretty major issue that has been resolved with this new Beta driver release. Sebastian Castellanos goes on to say that games like Rise of the Ronin, Star Citizen, and Valheim are similarly affected by this Windows 11 bug.
It's unclear whether this issue is limited to NVIDIA graphics cards, as AMD hasn't confirmed whether Radeon GPUs are affected. Also, as a GeForce Hotfix Display Driver, it requires manual installation with the update on track to be included in the next official GeForce Game Ready Driver release.




