This recent Windows 11 update could ruin your gaming frame rates, tanking Assassin's Creed Shadows by up to 50%

It's looking like Microsoft just gave us yet another reason to complain about Windows 11. Along with the unwanted CoPilot AI intrusion, adverts in its search, and the incessant badgering to switch over to Edge or use OneDrive, now Microsoft's OS could be killing your frame rate too, if you've updated recently.

Rumblings about frame rate issues with the recent October security and feature patch for Windows 11 (KB5066835) have continued since its launch, but new testing by Digital Foundry has definitively shown that the update destroys gaming PC performance in at least one game. Only by applying a recent Nvidia driver hotfix can the issue be somewhat solved.

The tech site tested the Windows update issue by running a set of benchmarks in Assassin's Creed Shadows, using an AMD Ryzen 9800X3D and an Nvidia RTX 5090. Observing "remarkably low" frame rates, the site then installed Nvidia's hotfix driver, which specifically addresses "Lower performance […] in some games after updating to Windows 11 October 2025 KB5066835." With the fix installed, frame rates jumped up.

The site doesn't state an exact change in the average frame rate, but the screenshots it provided (below) show the same point in the game before and after the hotfix as having frame rates of 34fps and 72fps, respectively. They also point out that the recent Windows update, if not patched, dropped performance in this game by between 33 and 50%.

While this finding was definitive, it is only one game, and Digital Foundry didn't test any others. However, another user on X (formerly Twitter) tested the hotfix in CS2 and reported an 11% increase in 1% lows (the average 1% of lowest frame rates) with the hotfix applied. Meanwhile, Nvidia's documentation for the hotfix does state that it fixes "some games" without citing any particular titles, so it's reasonable to assume there are a number of other games affected.

What isn't currently clear, though, is whether this is an issue unique to Nvidia GPUs or if it affects AMD graphics cards as well. More testing will be needed to fully get to the bottom of the issue. However, if you are running a recent Nvidia GPU and experiencing changes in game performance following a Windows update (or you've just noticed some slowdown recently), it's well worth downloading Nvidia's hotfix.