Windows 11 KB5066835 Update Triggers Major Gaming Performance Regression

Further Testing Shows How an NVIDIA Hotfix Driver Restored FPS to Games Following a Microsoft Update That Had Reduced Them

Image: NVIDIA NVIDIA has rolled out its own fix after it was discovered that a now-infamous Windows update caused even more problems than previously known. At this point, the Windows 11 update known as KB5066835 could, more or less, be thought of as the update that broke Microsoft’s latest OS, and while it remained functional for many, there were also many problems introduced that required fixing. Before digging into the newest findings regardin…

Windows 11 KB5066835 Update Triggers Major Gaming Performance Regression

Microsoft’s October 2025 cumulative update for Windows 11 is causing unexpected and severe slowdowns in several PC games. Update KB5066835, deployed across Windows 11 24H2 and 25H2 systems, has been linked to performance drops reaching up to 50 percent in certain titles.