Benchmark shows Windows 11 update dropped frame rates by 50% before Nvidia hotfix driver

After an October Windows 11 update, some gamers began experiencing stuttering gameplay. Nvidia addressed the issue on November 19th with a hotfix driver. How negatively the KB5066835 security patch impacted some titles wasn’t obvious until now. Digital Foundry ran benchmarks for Assassin’s Creed Shadows, confirming at least a 50% performance drop in some scenes.

The problems surfaced after the patch for the Windows 11 24H2 and 25H2 updates started rolling out. It remains unclear what caused the shockingly low framerates, with few details provided. Still, in the recent 581.94 hotfix, the graphics card maker noted, “Lower performance may be observed in some games after updating to Windows 11 October 2025 KB5066835.”

Digital Foundry conducted tests using a Ryzen 7 9800X3D processor and RTX 5090 GPU. Despite the high-end hardware, Assassin’s Creed: Shadows exhibited significant frame rate drops before Nvidia's solution. At 4K resolution, max graphical settings, and with DLSS quality mode active, the results went from 34 fps to 72 fps following the fix.

Who is responsible for the Windows update performance issues?

The scores align with the differences other gamers have seen since the Nvidia driver update. Nevertheless, the Digital Foundry team issued scathing criticism of Microsoft. The broadcasters suspect DX (DirectX) conformity issues may have been a culprit. However, the lack of communication between the company and GPU manufacturers also worsened the situation.

Alex Battaglia called Microsoft an “absolutely terrible steward for their operating system.” The panel also believes that Windows 11 is too reliant on Nvidia to maintain and enhance gaming performance. With so much focus on AI features, there is a “fundamental lack of leadership in Windows gaming at the moment.”

Xbox gaming has introduced significant changes over the past months. Its Full Screen Experience is now available on more gaming handhelds and will soon come to PCs. Even so, the frame rate gains from the gaming-focused UI are minimal, and new bugs have cropped up. As Windows updates continue to cause chaos, the upcoming Valve Steam Machine and its SteamOS seem more tempting.